Since you don't mind mountains, Hwy 50 to Montrose then jump on 550 south. How to get to hwy 50 depends on where you exit RMNP, or how direct of a route you want.
It would be my preference but I love mountain driving.
It's the screaming people in the passenger and back seats that bother me.
But no help with campgrounds. Only campground in that area I stay at are FS with limited access for large trailers, or you need a 4x4 with very high clearance to get into.