I travel the UP roads often in our 43ft towing a full size Ram truck without any issues. Most of the roads running south out of Munising are good. US 2 following the top of Lake Michigan is a major 2 lane highway. Down into Wisconsin is similar to the UP. In my opinion, much easier to drive in that area than most other areas of the country.
I assume you have a RV GPS, use it to avoid gravel roads.
2007 Haulmark 3301ds
2019 Ram 1500