Could you advise us what to keep in mind when traveling this general area?

If you want to continue up north, I’d advise you to take the way across the mountains. These days, the dangers from marauding bands of orcs and wild animals are lower there than on the main roads.

And how about traveling by the river?

You can still use the Svellt embankment as far as Lowangen, but from there, it becomes too dangerous because of the blackpelts. Still, you can reach Tjolmar via Thasch and the Blood Peaks.