We are from Pa and have been to both on separate trips.First would be to choose your route. I would suggest I-64 to Missouri then I-44 to I-40 to get to the Grand Canyon. We prefer state parks for our over nights because of the price. When we went to the Yellowstone, prices in State Parks with electric hookups ranged from $16 a night in Iowa to $26 in Ohio.We stayed at the Circle Pines KOA in Williams Arizona.They have an indoor pool and hot tubs. It's about 50 miles to the Grand Canyon or you can go into Williams and take the train.In Arizona we also headed south to Cottonwood and stayed at Dead Horse Ranch State Park.They have water and electric. You are very close to Jerome, an old mining town and Tuzigoot, Indian ruins from around 1300 AD. We also visited an old Calvary Post in Ft Verde.It's definately worth a day trip if you like history.From Arizona, I would head north on I-15 and go in the entrance at West Yellowstone.We stayed in Madison Campground right in the park.If you want hookups,Fishing Bridge is the only campground in the park with them.You should stay in the park because it's as big as the state of Rhode Island and you will be doing alot of driving. If you come back on I-80 through Nebraska,I would highly recommend stopping at the Harold Warp Museum in Minden Nebraska.If you like history,old cars, trucks,motorcycles or snow mobiles, you will love this place. They have a campground there and while it's not the greatest,it has full hookups and is ok for an overnight stop. Plus, they give you one free ticket to the museum with your stay.One more piece of advice. Instead of taking I-70 across Missouri, take RT 36. It's 4 lane and 65mph.We stayed at Pershing State Park which is right off Rt 36. A nice park with electric hookups.
