4 seasons toy haulers under 5000lbs dry weight?

I wouldn't avoid cold weather in "any" toyhauler. Our very first trip out in our Momentum 350G was a weekend stay at an RV park in Beaver, UT, in early January. Night time temps were in the low teens, and daytime temps in the low 30s. We had no problems from the cold weather, or anything else for that matter. We did burn about 5 gallons of propane running the furnace that weekend though. And our 350G is somewhat over the 5000 lb dry weight the OP asked about.