Here’s my translation

Alan

En þeir eru svá varir um sik, at þeir hafa njósn á hverri götu ok í hverri höfn, ok má þeim ekki á óvart koma, en þeim þykkir aldri örvænt, nær þeir Herrauðr ok Bósi koma at vitja meyjarinnar. 
But they are so on their guard (lit: aware concerning themselves), that they have (ie maintain) surveillance (njósn, Z1) on every road and in every harbour, and (one) may not come upon them unaware (ie not take them by surprise), and (it) seems to them ever nearer (aldri, Z2, after negative, nær = nærri, Z6?) beyond-expectation, (that) they Herrauðr and Bósi come to fetch the maiden. (ie the more time goes by, the less likely it is that they will see Bósi and Herrauðr)

Konungr hefir látit gera sér höll svá mikla, at á henni eru hundrað dyra, ok er jafnt langt í millum allra; hundrað manns má rúmliga sitja í millum hverra dyra; tveir dyrverðir eru við hverjar dyrr, ok á þar engi inn at ganga, sá sem eigi er þekktr við einhverjar dyrrnar, en þann, sem við engar er þekktr, skal taka ok hafa í varðhaldi, þar til at prófat er, hverr maðr hann er. 
(The) king has caused to build for himself a hall so large, that on it are a hundred (of) doorways, and (it) is equi-distant (equally long) between all; a hundred (of) person(s) may roomily sit between each doorway; two door-keepers (dyrr + vörðr) are by each doorway, and no-one has a right (á, eiga, Z4 to go inside there, that-one (ie, he) who is not recognised (þekkja, Z2) at (the) some doorways, (but) and (one) shall take (seize) and have into custody that-one (þann, accusative, ie him,), who is recognised by none, until (it) is proven, which person (man) he is.

Sæng stendr á miðju hallargólfi, ok er þar fimm palla upp at ganga. 
A bed stands in (the) middle (of the) hall-floor, and five (of) steps are (lit: is) there to walk up.

Þar skal liggja brúðrin ok brúðguminn, en hirðin öll skal vaka um kringum, ok má þeim því ekki á óvart koma.
The-bride and bride-groom shall lie there, but (and) all the-king’s-bodyguard shall keep-awake (ie keep vigil) around (them), and (one) may not therefore come upon them unaware (ie not take them by surprise).

"Hverir eru með konungi?" segir Bósi, "þeir sem hann heldr mest af?"
“Who are with the-king?” says Bósi, “those who he makes most of (ie values most, cf halda mikit af e-m, Z8)

"Sá heitir Sigurðr," sagði hún, "hann er ráðgjafi konungs ok svá mikill meistari til hljóðfæra, at hans líki er engi, þó at allvíða sé leitat, ok þó mest á hörpuslátt. 
“That-one (ie he) is-called Sigurðr,” said she, “he is counsellor (lit: advice-giver) of (the) king and also a great master of musical-instruments (plural), that no-one is his like (equal), even-though (he) be sought very-widely, and nevertheless greatest at striking-a-harp.

Hann er nú farinn til frillu sinnar; hún er ein bóndadóttir her við skóginn, ok lætr hann sauma sér klæði ok semr hljóðfæri sín."
He is (has) now journeyed to his concubine; she is a certain farmer’s-daughter here by the-wood, and he causes (her) to make-by-sewing his clothes and (he) tunes (semja) his instrument (which instrument would that be? 😊)

Ok fellr þar nú tal þeira, ok sofa þau af um náttina.
And their conversation now falls (ie subsides) there, and they sleep the night through

12. Frá brullaupsveizlu.
12. About the wedding-feast.

Um morguninn snemma kemr Bósi til Herrauðar ok segir honum, hvat hann hefir frétt um náttina, ok síðan bjuggust þeir frá bónda, ok gaf Bósi dóttur hans fingrgull, ok fóru þeir nú at tilvísan hennar, þar til at þeir sá þann bæ, er Sigurðr var á. 
Early the next morning Bósi comes to Herrauðr and says to him, what he has heard during the-night (expurgated), and after-that they readied-themselves (to go) from (the) farmer, and Bósi gave his (ie the farmer’s) daughter a gold-finger-ring, and they journeyed now according to her direction, until they saw that farmstead, that Sigurðr was (ie stayed) at.

Þeir sá nú, hvar hann fór ok einn sveinn með honum ok stefndu heim til hallarinnar. 
They saw now, where he journeyed and one servant-lad with him and headed home to the-hall.

Þeir gengu nú á veginn fyrir Sigurð. 
They went (on foot) now on the-way before (in front of, ie to intercept) Sigurðr

Bósi rak spjótit í gegnum hann, en Herrauðr kyrkti sveininn til bana.
Bósi drove the-spear through him, but (and) Herrauðr strangled the-servant-lad to death.