We were last at Dinosaur NM for a few days in late October 2020. Definitely see the new quarry exhibit, but we also like many of the back roads. If you are staying in Vernal, check out the Split Mountain Campground. For back roads check with the park for current conditions, but I think some of them are OK for your short class C if you have experience driving back roads, go slow and use caution.
We have several posts on our blog from that visit, including McConkie Ranch petroglyphs.
http://arts-work.blogspot.com/2020/10/dinosaur-national-monument-part-1.html