Here’s my translation

Alan

Þeir sáu fyrir virki hátt og er þeir komu þar hófu þeir Þóri upp á spjótaoddum. 
They saw in-front a high castle and when they came there they raised Þórir (accusative) up on spear-tips (plural) (some circus act!).

Þá krækti hann öxi sinni upp á virkisvegginn og las sig svo upp. 
Then he hooked his axe up onto the castle-wall and so picked (raised) himself up (onto the wall)

Lauk hann þá upp virkinu fyrir félögum sínum. 
Then he opened  up the castle for his comrades (ie so that they could enter).

Gengu þeir þá inn með öll föng sín. 
Then they went (on foot) inside with all their baggage.

Þórir lauk upp skálann og voru þar tólf manna rekkjur og tvær mestar. 
Þórir opened up the-(sleeping-) hall and twelve beds of (for) men (persons) were there and two (of the beds were) (the) largest.

Virkið var öruggt vígi. 
The-castle was a secure stronghold (vígi)

Þórir bað þá vörð halda og svo gerðu þeir.
Þórir bade them to hold (keep) watch (vörðr, Z2) and they did so.

En litlu síðar sáu þeir tólf menn, mjög víglega, ríða að virkinu og voru tveir mestir. 
But (And) a little later they saw twelve men (persons), very war-like, ride to the-castle and two were (the) largest) (mirroring the beds)

Þeir spyrja er til komu hverjir svo djarfir væru að tóku virkið með valdi. 
They asked when they came to (the castle) who were so bold that took (ie that had taken) the-castle with power (by force)

Þeir Þórir sögðu til sín og spurðu hverjir komnir væru. 
They Þórir (and co) gave their names (lit: spoke as regards to themselves, segja til sín, Z5) and asked who were (had) come.

Sá nefnist Hauknefur er svaraði en annar Hama. 
That-one (ie he) who answered named-himself Hauknefr but (and) (the) second Hama.

Hann var af Helsingjalandi en Hauknefur af Gestrekalandi. 
He was from Helsingjaland (Hälsingland aka Helsingia, Central Sweden) but (and) Hauknefr from Gestrekaland (Gästrikland, East Sweden, neighbours on Hälsingland).

Þeir báðu þá Þóri út ganga.
They bade then Þórir to walk outside.

En Þórir segir að hann vill berjast með jafn marga menn "og skulu tveir af vorum mönnum berjast við tvo yðra menn."
But (And) Þórir says that he wants to do-battle with equally many men (persons) “and two of our men (persons) shall do-battle against two men (persons) of yours.”

Þeir vilja það. 
They want that.

Þórir og Ketilbjörn börðust við tvo af stigamönnum og hjó sitt högg hvor þeirra og varð hinum það þegar að bana. 
Þórir and Ketilbjörn did-battle against two of (the) ‘highwaymen’ and each (of the two, hvárr) of them delivered his blow and that became (ie was) for the-others (ie the highwaymen) immediately (the cause of their) death (see verða at bana, under verða, Z8)

Eftir það börðust þeir allir og varð það harður atgangur en svo lauk að þeir féllu allir nema tveir, Hauknefur og Hama. 
After that they all did-battle and that became a hard-fought combat but (and) (it) concluded thus that they (ie the highwaymen) all fell (in battle) except two, Hauknefr and Hama.

Þeir voru þó mjög sárir. 
They were nevertheless very wounded

Þórir bauð Hauknef grið og báðum þeim og því játta þeir skjótt. 
Þórir offered (bjóða) Hauknefr a truce and to them both and they agreed (said-yes) to that speedily.

Síðan gengu þeir til handa og félags við Þóri og skiptu að jafnaði öllu því fé er þar var og fóru af skóginum er þeir voru búnir, fyrst til Svíþjóðar en þaðan til Gautlands og fundu þar Hlöðvi jarl son Æsu hinnar örðigu Hlöðversdóttur. 
After-that they (ie Hauknefr and Hama) put-themselves into the hands of (ie submitted to) and into fellowship with Þórir and divided in equal proportions (they must have learnt from their previous divvying-up fiasco J) all that wealth which was there and journeyed from the-forest when they were ready, firstly to Sweden and from-there to Gautland and found (ie met) there Earl Hlöðvi son of Æsa the Harsh,(note comma J) daughter of Hlöðverr.

Hann gekk þegar við frændsemi við Þóri er hann sagði ætt sína. 
He immediately acknowledged Þórir as a kinsman when he (ie Þórir) said (ie recited) his pedigree.

Þeir voru þar landvarnarmenn um hríð og gerðust víðfrægir.
They were there entrusted-defenders-of-the-country-against-invaders (Home-Guard) for a while and became far-renowned.

6. kafli
Chapter 6

Ásta hét dóttir jarls. 
(The) daughter of (the) Earl (ie Hlöðvi) was-called Ásta.

Hennar bað Gautur berserkur, mikill kappi. 
Gautr (the) berserk-warrior, a great hero, asked for her (in marriage)

Hann var sænskur að ætt. 
He was Swedish (soenskr) by descent.

Með honum var Geir hinn gerski og höfðu mikla sveit en jarl vill eigi gefa konuna.
With him was Geirr the Garðarikian (Russian) and (they) had a great-body-of-men but (the) Earl does not want to give (in marriage) the-woman (ie Ásta) (to him).