Southern Colorado along US 160 from South Fork to Durango is beautiful with lots of campgrounds and RV parks. Keep in mind that the elevation ranges from about 6,500' at Durango to over 8,000' at South Fork. Temps are typically cool even in the summer reducing the need for air conditioning and therefore 50 amp. Near South Fork we have even run the furnace some nights in July. And you would get to travel over La Veta pass at 9,400' and Wolf Creek pass at 10,800'.
The Cumbres & Toltec steam railroad (Antonito, CO to Chama, NM) is also a great train ride.