> Þeir leita stóðhestsins um hlíðina og fundu hann meðal lækja tveggja
og leiddu hrossin ofan að götum mjög.

> They saw the Stallion on a slope and found him between two brooks
and brought the horse down to a good road (? a wider road for safety)

hrossin "horses" (neuter plural + definite article -in).
að götum mjög. MM & HP "far down towards the road" (actually 'götum'
= dative plural of 'gata'). Compare: Var þá mjög kveldið á liðið "It
was now very late in the evening" (Laxdoela saga 62), trans. MM & HP.
And Zoega's example 'hann var dauðr mjök af kulda' "he was nearly
dead of cold."