We used route 139 north from Grand Junction on our way to Vernal back in 2012. We have a 24 ft MH with no toad. I do recall one sharp curve where I was glad that there was no one coming in the opposite direction. We did have several 18 wheel trucks pass us along the way. I don't recall any issues going back down toward Dinosaur.
A couple of pictures looking back down the road from Grand Junction:
Yes, that's a truck coming up the grade.
Nearly to the top.
2003 Winnebago Minnie 24F - Ford E-450๐