Here’s my translation

Alan

Snorri mælti: "Miklu er þér meiri vandi á að gera eftir vorum vilja.
Snorri spoke: „“(The) obligation (vandi, Z3) is by-far greater for you to act according to (eptir) our wish.

Er þér og þetta sjálfum höfuðnauðsyn því að þú færð aldrei slíkrar konu sem Guðrún
This is also for you yourself (sjálfum dative goes with þér, dative) a great-need because you would never get (fá) such a wife as Guðrun

er þótt þú leitir víða."
is even-though (þótt) you searched far-and-wide.”

Og við umtölur Snorra og það með að hann sá að hann mælti satt
And with (ie by means of, við, Z10) (the) persuasions (fem acc pl, see umtölur, CV, this is not umtal, and not dative) of Snorri and that with (it), that (at, conjunction, refers back to Það) he (ie Þorkell) saw that (at, conj) he (Snorri) spoke truly (satt is neut of sannr, adj used here as adv)

þá sefaðist Þorkell en Gunnari var í brott fylgt um kveldið.
then (þá, adverb) Þorkell (nominative) was-appeased but (and) Gunnarr (dative) was led (impersonal construction, e-m fylgja, Z2, fylgt is past part) away during (um, Z6) the-evening.

Veisla fór þar vel fram og skörulega. Og er boði var lokið búast menn í brott.
(The) feast (veizla, Z3, veisla is modern spelling) went well there-from (ie from that point) and magnificently. And when (the) (wedding) feast (dative sg of boð, the object of lokið), was concluded (lokið is past part of lúka e-u, Z4 impersonal construction), people (men) readied-themselves (to go, implied) away.

Þorkell gaf Snorra allfémiklar gjafir og svo öllum virðingamönnum.
Þorkell gave to Snorri (dative) very-costly (fem acc pl of allfémikill, adj) gifts and also (svá, svo is modern spelling) to all persons-(men)-of-distinction (masc pl dative. dative like Snorra because they are also the recipients of gifts).

Snorri bauð heim Bolla Bollasyni og bað hann vera með sér öllum þeim stundum
Snorri offered (his) home to Bolli (dative) Bolli’s-son (dative sg) and bade him to be (stay) with him for all those times

er honum þætti það betra. Bolli þiggur það og ríður heim í Tungu.
when that seemed (past tense subjunctive of þykkja) to him better (ie for as often and as long as he liked). Bolli (nom) accepts (present of Þiggja, Z1) that and rides (present) home to Tunga (Tongue).

Þorkell settist nú að Helgafelli og tekur þar við búsumsýslu. Það mátti brátt sjá að
Þorkell set-himself (ie settled) now at Helgafell and takes (accepts) there-with (ie along with it) (the) management-of-the-farm. (One) might soon see that, that

honum var það eigi verr hent en kaupferðir. Hann lét þegar um haustið taka
that (ie farming) was to him not worse suited than trading-journeys (voyages). He caused at-once during the-autumn to take

ofan skála og varð upp ger að vetri og var hann mikill og risulegur.
down (the) hall (ie house) and (it) became (was) rebuilt (restored, göra upp, Z13) at-the beginning-of (ie in time for, see at, Z.iii.1) winter and it was tall and stately.

Ástir takast miklar með þeim Þorkatli og Guðrúnu. Líður fram veturinn.
Love grew great between them, Þorkell and Guðrún. Winter passes away (impersonal construction, líða fram e-t, Z6).

Um vorið eftir spyr Guðrún hvað hann vilji sjá fyrir Gunnari Þiðrandabana.
During the-spring (vár) after Guðrún asks what he wants to see for (ie how he wants to provide for, what he wants to do with) Gunnarr Þiðrandi’s-slayer.

Þorkell kvað hana mundu fyrir því ráða: "Hefir þú tekið það svo fast að
Þorkall declared her (that she) would be-master of that (see ráða fyrir e-u, Z16): “You have taken that so hard (firmly) that

þér mun ekki að getast nema hann sé sæmilega af höndum leystur."
(it) will not please you (getast at e-u , Z6) unless he is honourably set-free from hands (from the clutches of the law?).”

Guðrún kvað hann rétt geta "vil eg," segir hún, "að þú gefir honum skipið og
Guðrún declared him to guess right (geta, Z.ii.1) “I want,” says she, “that you give him the-ship and

þar með þá hluti sem hann má eigi missa að hafa."
there-with (ie along with it) those things that he may not suffer (hafa, Z8) to do-without (feel the want of, missa, Z3)

Þorkell svarar og brosti við: "Eigi er þér lítið í hug um margt Guðrún,"
Þorkell answers and smiles with (it, in reply): “)(There) is not for you little in mind concerning many (things) (you are always thinking big?), Guðrún,”

segir hann, "og er þér eigi hent að eiga vesalmenni. Er það og ekki við þitt æði.
says he, “and (it) is not fitting for you to have (ie have as a husband, in marriage) a paltry-person. That is also not with according-to your nature (oeði, ie it does not suit thee)

Skal þetta gera eftir þínum vilja."
(I, one) shall do this according-to your wish.”

Fer þetta fram. Gunnar tók við gjöfinni allþakksamlega: "Mun eg aldrei
This goes forward. Gunnar received the-gift very-gratefully. “I will never

svo langhendur verða að eg fái yður launað þann sóma allan sem þið veitið mér."
become (be) so long-handed (having the ability to dig deep into one´s pockets (?),presumably an allusion to being wealthy or powerful ?) that I am-able to repay you all that honour which you-two are-granting me.”

Fór Gunnar utan og kom við Noreg. Eftir það fór hann til búa sinna. Gunnar
Gunnarr goes abroad and came against (ie touched, reached) Norway. After that he journeyed to his farm. Gunnarr

var stórauðigur og hið mesta mikilmenni og góður drengur.
was very-wealthy and the greatest man-of-power and a good man-of-nobility.