I go the opposite way in the winter. Everything is closed camping wise in regard to public campgrounds from Iowa or Missouri on up so we boondock camp at Cabelas, Walmart or Cracker Barrel. Most private campgrounds are closed too. Last year we did camp in a state park in Oklahoma that was open but there was no water and the toilet rooms were locked up. It was below freezing there. The plains states can be brutal in the winter so my advice is to head directly east and then take I-35 north. You will have the protection of the frequent rest stops.
We are thinking about traveling from AZ to Rochester, MN for xmas. Our daughter and her family will have quarantined for 2 weeks prior to our arrival. Might bail if things get as bad as predicted. But if we do go, do you have suggestions as to route at this time of year and possible places to camp along the way. I suspect that I'll have to winterize the water system. Not a big deal since we don't use FW tank water for drinking or cooking. We'll be able to do a dump at their place via their sewage cutout after arriving so dumping is not an issue.