Wow G&C,
We finally get a nubee that is not a dreamer.... Great.
Start by planning to recoat, seal or caulk the entire roof and put it on your calendar to inspect it twice a year. As stated above this is THE Primary COD of RVs of all types.
The next big killer of both owners and coaches is tires. They may look great but the binders have aged out. If the inside dual got run low at any time, its life will be even less than the 7~8 years that is the current target. Find the DOT dates on all the tires. They are probably over age. Plan on replacing all 7. Get valve stem extensions so you can check them regularly.
Next, but not big, look up and consider joining FMCA. It is not expensive and they have a lot to offer.
Not as important, is plan to carry your own wire (internet). No public access can be counted on to be worth a tinkers devil. This is easy to do now, but shop a lot as suppliers and plans very widely. It is almost universally accepted here that Verizon has the best coverage, but still plan to be out of coverage for a day at a time when not near major urban areas.
Lastly, enjoy the journey. I don't know what you and yours like and enjoy, but I bet that there is more of it in this country than you ever imagined. The trick is finding it. I use AAA, Trip Adviser and Furkot all at the same time.
Matt