> Búi sagði af hið ljósasta "og vildi eg þiggja veturvist
> með yður herra."

> Bui declared most clearly "I also wanted to receive a
> winter abode (a place to crash for the winter) from your
> lordship.

> Bui told of (himself) in the clearest (way) “and I would
> want to receive hospitality of a winter visit with you,
> Lord.”

> Búi said (rattled off? said of (it, himself), I´m not sure
> what “af” is doing here) the most-plain (answer) “and I
> would-want to receive a winter-stay (winter-lodging) with
> you, lord.”

<Segja af e-u> is 'speak of something'; I take the sense to
be 'Búi spoke thereof most clearly', meaning that he very
clearly identified himself.

> Jarl segir: "Fylgd góð mun í þér.

> (The) earl says: "You will accompany me. (??)

> (The) earl says, “Good help? will (be) in you.

> (The) earl says: “Good support will (be) in you (you will
> be useful to us?).

My guess is that the support in question is to be understood
as being principally martial.

> Steinker (Stone-Tubs)

Now Steinkjer, in Nord-Trøndelag. The name refers a dam,
embankment, or (bridge) pier of stone, or to a damming up
for catching fish; according to Bokmål Wikipedia, three
rivers that empty into Trondheimsfjord here have always been
good salmon rivers.

Brian