I live in the UP, and thought I knew "desolate", but I would warn you (especially in summer) to stop at the nearest superstore after picking up your vehicle and stocking up on everything you might need or want while on the road. Many small towns won't have a grocery store, and some won't even have a convenience store. I would plan on buying cheap coolers, plenty of water, snacks that can stand the heat of summer in a vehicle, etc, etc. Also, do NOT count on cellphone coverage everywhere, either download maps ahead of time, bring/buy actual paper maps (gasp, I know, but the gazetteer we bought really helped when we were off the four lane), etc. Fill up your gas tank when you see a station, not when you're getting low. If you're going to eat out, don't count on restaurants being open late if you aren't in a major city.
One thing we didn't do (due to the weather), but could have done easily was buy a cheap tent/sleeping bags from Walmart down there, and drycamped many, many places. We even debated sleeping in the back of the SUV a few times, because many people do it. My old bones decided that $50 for a basic but clean motel was worth it, but there were a few beautiful locations that we would have loved to sleep under the stars.
Most of all, take the time to get off the beaten path, and just enjoy. We actually cut the Grand Canyon out of our trip (gasp, I know, but it was thanks to advice from this board), and we still had plenty to do in our two weeks.
Terri