The first half of the last sentence was certainly ...
interesting.

> Nú verða við varir Skógstrendingar, Þorgestur hinn gamli
> og Áslákur úr Langadal.

> Now Thorgestr the old, and Aslakr from Long-dale heard the
> Forest-(trendings). (CV varr - verða varr við e-t, to be
> aware, of, learn, hear)

> Now the Skogstranders became aware (of what was
> happening), Thorgest the elder and Aslak of Langadal.

Now the Skógstrendings, Þorgest inn gamli [‘the old’] and
Áslák from Langadal, become aware (of what’s happening).

> Þeir hljópu til og gengu í milli, en hvorirtveggju voru
> hinir óðustu, og fengu eigi skilið þá áður en þeir hétu að
> veita þeim er þeirra orð vildu heyra til skilnaðarins, og
> við það urðu þeir skildir og þó með því móti að
> Kjalleklingar náðu eigi að ganga upp á völlinn og stigu
> þeir á skip og fóru brott af þinginu.

> They sprang to and went in the middle, end each of the
> two was the most furious, and they were not able to break
> off then before that they called to help them which their
> word would hear to the parting, and with that they became
> shields and although with that against the Kjalleklings
> were not able to go up on the field and (they) went on
> board their ship and immediately went away from the Thing.

> They ran towards (the skirmish) and went between, but each
> of the two (sides) were the most furious, and (they) were
> not able to separate them before, but they promised to aid
> those who wished to hear their words about separating, and
> with that they became separated and yet in that way that
> (the) Kjalleklingers were not allowed to go up on the
> field and they boarded a ship and went away from the
> Thing.

They ran up and went between (the two sides), and both
(sides) were the most furious, and they were not able to
separate them before they promised to help those who would
hear their words concerning the separation, and with that
they were separated, though in such a manner that the
Kjallelklings were not able to go up onto the field, and
they boarded a ship and went away from the þing.

> Þar féllu menn af hvorumtveggjum og fleiri af
> Kjalleklingum en fjöldi varð sár.

> Men fell there from each pair and more of the Kjalleklings
> and a multitude became wounded.

> There men fell from both sides and more from the
> Kjallekingers, and many were wounded.

There fell men of both (sides), and more of the
Kjalleklings, and a multitude were wounded.

> Griðum varð engum á komið því að hvorgir vildu þau selja
> og hétu hvorir öðrum aðförum þegar því mætti við koma.

> The truce happened (that) no one came on (?) because
> neither of them wanted to give up and call each other the
> attach at once that could be convenient. (??)

> A truce was not arrived at because neither wanted to
> accept (pardon) and each promised execution for the other
> as soon as it might come about.

No truce was effected, for neither (side) wished to offer
it, and both promised other attacks as soon as might be
convenient.

<Grið> 'truce' is actually plural, hence <þau> in <þau
selja>, but English requires singular 'it'.

> Völlurinn var orðinn alblóðugur þar er þeir börðust og svo
> þar er Þórsnesingar stóðu meðan barist var.

> The field had become bloody all over there where they
> fought and so there where the Thornessings stood while
> (they) had fought.

> The field had become all bloody there where they fought
> and also there where the Thor’s Ness folk stood while (the
> battle) was fought.

The field had become bloody all over where they (had)
fought, and (al)so there where the Þórsnesings stood while
the fighting was going on.

> Eftir þingið höfðu hvorirtveggju setur fjölmennar og voru
> þá dylgjur miklar með þeim.

> After the Thing each of the two had placed a great many
> people and (there) were then many suppressed enmities
> between them.

> After the Thing, each of the two sides had many men in
> place and then (there) was surpressed enmity between them.

After the þing both (sides) had set up large companies, and
there was then much suppressed enmity between them.

> Vinir þeirra tóku það ráð að senda eftir Þórði gelli er þá
> var mestur höfðingi í Breiðafirði.

> Their friends took the course of action to send for Thord
> "yeller" who was the greatest chieftain in Broad-fjiord.

> Their friends decided on a plan to send for Thord yeller
> who then was the greatest chieftain in Breidafirth.

Their friends adopted the plan of sending for Þórð gellir,
who was then the greatest chieftain in Breiðafjörð.

> Hann var frændi Kjalleklinga en námágur Þorsteins.

> He was a relative to the Kjalleklings and an in-law of
> Thorstein.

> He was a kinsman of the Kjallaklingers and a closely
> related by marriage to Thorstein.

He was a kinsmen of the Kjalleklings and Þorstein’s near
relative by marriage.

> Þótti hann líkastur til að sætta þá.
> He was thought most likely to reconcile them.
> He seemed most likely to reconcile them.

He was reckoned most likely to reconcile them.

> En er Þórði kom þessi orðsending fór hann til við marga
> menn og leitar um sættir.

> When this message came to Thord, he went with many men and
> tries to effect a reconciliation.

> And when this message came to Thord, he went with many men
> and seeks reconciliation.

And when this message came to Þórð, he travelled there with
many men and tries to effect reconciliation.

(Technically <sættir> is plural.)

> Fann hann að stórlangt var í millum þeirra þykkju en þó
> fékk hann komið á griðum með þeim og stefnulagi.

> He found that a very long (very long what?) was between
> them, it seemed that yet he got come to a truce with them
> and an appointment for a meeting.

> He found that a great distance seemed to be? between them.
> But still he was able to come to a settlement with them
> and appointment for a meeting.

He found that (there) was a very great distance between
their views, but nevertheless he was able to reach a truce
between them and an appointment for a meeting.

<Þykkju> is the acc. of <þykkja> 'thought, sentiment,
disposition' (Z1); it's feminine, so it can't be modified by
<stórlangt>, which is neuter. <Stórlangt> must then be
functioning more or less as a noun.

> Þar urðu þær málalyktir að Þórður skyldi gera um með því
> móti að Kjalleklingar skildu það til að þeir mundu aldrei
> ganga í Dritsker örna sinn en Þorsteinn skildi það til að
> Kjalleklingar skyldu eigi saurga völlinn nú heldur en fyrr.

> The conclusions became there that Thordr should arbitrate
> in such a way that the Kjalleklings stipulate that they
> would never go to their Dritsker islands and stipulate to
> Thorstein that the Kjallenlings should not defile the
> field now more than previously. (??) (Z. gøra 13 - g.
> um mál, to arbitrate in a case) (Z. mót 4 - með því móti,
> at, in such a way that) (Z. skilja 9 - s. e-t til, to
> stipulate) (Z. heldr 1 - h. en, rather than, more than)

> There the end of the case happened that Thord should do in
> that way that the Kjallaklingers decided that they would
> never relieve themselves at Dritskerry and Thorstein
> decided that the Kjallelkingers should not defile the
> field now (any) more than before.

The end of the matter there was that Þórð would judge in
such a way that the Kjalleklings stipulated that they would
never ‘do their business’ on Dritsker, and Þorstein
stipulated that the Kjalleklings should not now defile the
field more than before.

> Kjalleklingar kölluðu alla þá hafa fallið óhelga, er af
> Þorsteini höfðu fallið, fyrir það er þeir höfðu fyrr með
> þann hug að þeim farið að berjast.

> The Kjalleklings called all them (that) have fallen
> "unholy," which had fallen by Thorstein, for that which
> they had previously with that mind that they went to
> fight.

> The Kjalleklingers called all those to have fallen unholy?
> who had been falled by Thorstein, for that which they had
> previously with that thought that gone to fight them.

The Kjalleklings said (that) all those had fallen
unholy/outlawed who had fallen on Þorstein's (side), because
they had first gone at them with the idea of fighting.

<Alla þá hafa fallið óhelga> is an acc. + inf. construction
after <kölluðu> 'said'.

> En Þórsnesingar sögðu Kjalleklinga alla óhelga fyrir
> lagabrot það er þeir gerðu á helguðu þingi.

> And the Thornessings declared the Kjallenlings all the
> state of being outlawed for breach of law which they did
> at the holiday Assembly.

> But the Thor’s Ness folk declared the Kjallaklingers all
> unholy for breach of the law that which they did at a
> hallowed Thing.

But the Þorsnesings declared the Kjalleklings all
unholy/outlawed on account of the breach of law that they
committed at a sanctified þing.

> En þó að vandlega væri undir skilið gerðina þá játaði
> Þórður að gera og vildi heldur það en þeir skildu ósáttir.

> And though that carefully would be left to the fenced
> fields, then Thordr consented to do and wanted rather that
> than they decided un-reconciliation. (??)

> But even though it was a troublesome thing to decide upon
> then Thord agreed to do and wished rather that than that
> they part unreconciled.

<Gerðina> = <görðina>, fem. acc. sing. with def. art.; it's
the object of <undir>. <Væri> is 3rd person past subj., but
it could be either sing. or plur. Z. has <skilja e-n undir
sætt> 'to include one in an agreement, and CV s.v. <görð>
(II) has the idiom <skilja undir gerð> 'to stipulate (that a
judgement must include some feature)', with this sentence
from Eyrb. as an example. CV s.v. <skilja> (B.2) notes that
<skilit> can be 'reserved, stipulated'. Finally, the sense
clearly requires that <vandlega> be 'with difficulty' rather
than 'carefully'.

It was fairly easy to see that the sense must be that even
though the two sides' stipulations would make matters
difficult for the arbitrator, Þórð agreed to arbitrate,
preferring that to letting the sides part unreconciled. The
hard part was figuring out how to get that from the text. I
finally decided to take <væri> as 3rd person plural with an
implied subject 'these stipulations' and to treat <skilið
under gerðina> as parallel to <skilit undir sætt> rather
than exactly according to the CV gloss:

But although [these stipulations] would with difficulty be
incorporated into the judgement, Þórð agreed to arbitrate
and wanted that rather than (that) they parted
unreconciled.

Note that while I have no doubt that the basic sense is
correct, I'm not 100% certain of the analysis that I've used
to match it with the text.

Brian