Here’s my translation

Alan

Þeir fóru nú eptir blóðdrefjunum þangat til sem þeir komu at hömrum nökkurum. 
They now journeyed along (followed, fara eptir e=m, fara eptir e=u, Z18) the-drops-of-blood (ie the trail thereof) until they came to some crags (precipices, hamarr, Z3).

Þeir váru brattir ok hávir ok svá sléttir at eigi mátti klífa. 
They were steep and high (hár) and so smooth that (one) could not climb (them).

Þeir báðu Stíganda forvitnast á fjallit. 
They bade Stígandi to make-enquiries (go on a fact finding mission) on the-mountain

Hann rann upp bergit ok kastaði þá skónum ofan til þeira ok renna þeir báðir bergit á skónum. 
He ran up the cliff and cast then down the (his)-shoes to them and they both run (up) the-cliff on (in?) the-shoes.

Síðan ganga þeir um fjallit. 
After-that they go (on foot) across the-mountain.

En er þeir höfðu lengi geingit fundu þeir dal einn fyrir sér. 
But (And) when they had walked (typo presumably) for-a-long-time (lengi, Z1) they found a single dale in-front-of them.

Þar váru sléttirvellir. 
Level fields were there.

Þar sjá þeir níu tigi hrossa, ok var þar með einn hestr furðuliga fagr ok grár at lit. 
There they saw ninety (lit: nine tens of) horses and there-with (ie among them) was one stallion exceedingly handsome and grey in colour (litr).

Eitt flókafolald sá þeir. 
They saw one a young-foal-with-a-matted-coat. (flóki + folald)

Þat var at öllu skripiligt. 
It (ie the foal) was monstrous in all respects (at öllu, allr, Z5).

Hrossin öll lömdu þat ok óþægðu. 
All the-horses flogged (lemja, Z1) it and vexed  (úþægja) (it)

Hestrinn lagði þat í eineltu. 
The-stallion put it (ie the foal) into harassment (ie harassed it, lit: a single pursuing, ein + elta, a feminine noun, CV has eltur, fem plural)

Þótti þeim gaman at horfa á þetta.
(It) seemed to them (ie Knútr et al) and amusement to turn to this (ie that there was the prospect of entertainment in this, cf horfir til gamans, under horfa, CV2).

Þeir sáu helli stóran. 
They saw a large cave.

Þá mælti Knútr: “Hér muntu Hörðr eptir dveljast þó at mér þiki mikit fyrir at skilja við þik. 
Then Knútr spoke: “Here, Hörðr, you-will remain behind even-though I am unwilling (lit: it seems to me a great (thing) to take the step, þykkja, Z2) to part with you.

En nú er tími svá stuttr at vantækt er á hvárt vér náum heim stefnudeginum, þó at oss beri eigi til tafa. 
But now time is so short that (it) is a problematic (couldn´t find vantækt in CV or Z, but found the word used in several Facebook posts etc with apparently this sense?) on (as to) whether we (will) reach home on the-day-of-summons (ie first day of summer), even though (it) happens not for us as-a-result of delay (töf, CV) (ie even if we are not delayed)

En geym þú hellisdyr þessar þangat til sem ek kem aptr, því at þar liggr líf várt allra við ef nökkut tröll kemst út ór hellinum.” 
But watch you this cave-entrance (gram plural) till that time that I come back, because there-with lies our life of all (all our lives depend on it) whether some troll makes-his-way out out-of the-cave.

Síðan skilja þeir.
After-that they part.

Fara þeir Stígandi ok Knútr í burtu þangat til sem þeir koma at hólum nökkurum. 
They, Stígandi and Knútr, journey away until (þangat til sem) they come to some knolls (plural).

Þar sjá þeir svín mörg, ok váru þau þá komin í svefn. 
There they see many swine, and they (the swine) were then come into sleep (ie fallen asleep).

Eina gyltu sáu þeir liggja undir hamri einum. 
They saw one young-sow lie under a single crag.

Hana sugu tveir grísir. 
Two young-pigs sucked (súga) her.

Hon var svá mögr at hon gat varla risit. 
She was so lean (magr) that she could hardly rise.

En þegar at aðrir grísir fóru frá henni þá fóru aðrir til hennar at sjúga hana. 
But (And) as-soon-as the-one (set of) young-pigs went from her, then the-other (set) went to her to suck her.

Knútr gekk at háli einum ok mælti til Stíganda: “Hér munt þú eptir verða, ok bíða mín þangat til at þrjár sólir eru af himni. 
Knút walked to a single knoll (hvállr? = hóll, see above) and spoke to Stígandi: “Here you will stay (lit: be) behind, and wait for me, until three suns are from (the) heaven (sky) (ie until the sun sets three times, for three days)

En ef ek kem þá eigi aptr þá þarf eigi mín at vænta. 
But (And) if I come then not back then  (it) is not necessary to wait for (lit: expect, hope for) me.

En ekki skaltu við svínin eiga fyrr enn úr kulit er um mína komu. 
But you-shall not have anything to do with (eiga við e-n, Z10) the-swine before the-cold-breeze (of hope?) is out-of (it) (ie has faded?, possibly kulit is a past part but could find no such verb) concerning my coming (koma, noun).

Ok muntu þó ærit eiga at vinna.
And you-will nevertheless have enough to do (vinna, Z1).