I can't comment with confidence about the weather, though I don't think that would be a problem that early.
But I can comment with confidence about US 160 and US 84 because I have towed a fifth-wheel several times on each of these. (All the way from Walsenburg to Durango on 160, and all the way from Pagosa Springs to Santa Fe on US 84.)I have been over Wolf Creek Pass several times each way. It is certainly a "serious" pass but I have never felt any lack of confidence in towing over it.
As for US 84, the section between Pagosa Springs and Chama, NM is one of our favorites. There are some beautiful views, and no problems with towing.
