Yesterday we returned from a few days in Iceland.
Temps along the South coast varied from the low 50s to just above freezing. Daytime temps were in the 40s most of the time.
Altitude makes a huge difference, with colder temps and snow increasing as you move inland into the hills.
It was rainy with low clouds and winds of 20-30 mph, and occasionally higher. We saw winds of 30-40 mph at Keflavik airport yesterday afternoon. Occasionally skies would partially clear.
We didn't see many caravans (trailers), but those we did see were a little larger than the typical European caravan. I don't recall seeing any Class Cs, but no doubt there are some.
Seems like the thing to have would be a heavily insulated, off-road engineered, self-contained vehicle. Once off teh few paved roads it's a harsh place.
Crossing the ridge East of Reykjavik in the ring road yesterday morning we were in a light snowstorm almost the whole way.