With motorhoming, a good part of the potential enjoyment is traveling, unless you make it an endurance contest to get to Wally World like Chevy Chase. Make sure you have reservations to camp at Yellowstone. I would figure on 5-7 days each way having done the cross country thing a number of times. You need to stop every 150-200 miles at rest stops for you and the kids (and pets?) to walk around on solid ground for a while. Just the road noise, pounding from the highway, wind gusts and passing semi's is wearing on everybody's nerves. You will need to stop for gas and occasionally at a restaurant. You will need to pull into an RV park a couple of times, on the way, around 3-5PM , get hooked up and settle in for the night, get to sleep and be refreshed. In the morning you can dump your tanks and refill fresh water tank. Don't make the mistake of driving into the night, getting dog tired and hungry, and trying to find an acceptable RV park with vacancies. Other times you may be able to park overnight to sleep at a truck stop or Walmart where it is permitted. Make sure you have a plan where to stop for the night each day. Not all KOA's are good but you have some idea what they are and you can call ahead to make reservations. Do try to stop at some points of interest. We have always used AAA "trip tiks" with highlighted routes. Use a GPS to be sure where that next off ramp etc., will come up and get in the proper lane to make it easy. I never thought of this before but we lost our awning in strong head and crosswinds recently. While having the new $730 awning fabric installed, we had a $50 awning lock device installed to keep the awning from inflating, unfurling and getting shredded. Make sure that your tires are OEM brand and type and near new. Make sure that your brake fluid is flushed and changed and that the cooling system works properly on hot days. Of course make sure that your dash and roof A/C, generator, water heater and furnace etc are working properly long before you leave. Try to eliminate any unpleasant surprises. Take everbody's perscription meds and OTC personal needs items, tools and glues, battery chargers, cameras, etc. Make a good list of things to take and do before leaving. Careful planning is essential for a safe and fun "big deal" vacation like this. Bon Voyage