Having done just what you're planning a few times, having been an editor of RVparkreviews.com, and originally being from Connecticut, I thought I'd add my two cents. I always start by picking RV parks I must stay at, and go backwards from there. Places like Colter Bay, Blackwell Island, Bluewater Key, Buckhorn Lake, etc. are so nice that if I didn't make it into them I'd be disappointed. The rest is fill-in, and easy: 6 hours a day, stop along the way and smell the roses (e.g. the real arch in Kearney), and be able to adjust along the way for places you want to stay longer/shorter at. We like the internet to find fuel (websites of fueling companies), along with shopping (antiques, swap meets, walmart), and events (parades, art shows), and possible places to stay (revparkreviews.com). We have animals so keep up with dog parks and vets (on line). And have found an aircard from Verizon to be useful almost everywhere.
OP, another online resource if you are a Good Sam member - their trip planning feature. I use that all the time, great reference for rest areas, GS campgrounds, mileage, distance - etc.
How much time do you have for the trip? If you are going this summer, you need to make reservations NOW - for Yellowstone, Grand Teton (Colter Bay RV), and Trailer Village in the Grand Canyon. rough out a time line, allow some travel leeway, then make those reservations for your main destinations. The overnights can be figured out on the fly.
Begin your plans, and come back here for some more input. Lots of travel experience here - all willing to offer their suggestions.
'02 KOUNTRY STAR DP
2012 HONDA FIT "PUMPKINMOBILE"
GILLIGAN- 1ST MATE CAT - 3 HR TOUR