Heading out the first week in July to anyplace that is popular means finding a campground with out reservations is going to be very, very hit and miss - and National Park campsites book well in advance. Walmarts are good for one night only - and you must ask permission of the manager of the store to stay overnight. Also some Walmarts do not permit overnight parking due to local regulations. Check for signs as you enter the parking lot that may say no overnight parking. There are alternatives to Walmart - Cracker Barrel restaurants will allow you to overnight. Flying J/Pilot stations allow overnight parking (if you can get a space). Other truck stops allow overnight parking but you are in competition with the 18 wheelers. Many casinos allow overnight parking and usually have an RV lot set aside. Some Cabela's stores allow overnight parking. Always ask first. Any business that allows you to overnight in their lot expects that you are going to spend some money while there at that business. Be very careful where you stop, especially, if you just decide to pull over - and if something does not feel right - leave. There are websites that list free overnight parking for RVs.
As has been said, a first time trip should never be a long distance trip but if you are buying long distance and have to make the trip, it is a good idea to stay close to where you purchased and spend one or two nights in the RV. Get a feel for it and if you have any questions you can go back to the person you bought it from and get them answered.
Best suggestion - spend a lot of time with who you are buying if from and have him show you everything working = and how to get it to work. You want no surprises that this or that does not work - or you don't know how to get it to work. Don't let this be rushed and either video record the whole thing. Taking notes gets too confusing. Have them show you while your wife videos it.
Also if there is a manual for this RV you want it. If the owner does not have it look for it on the internet.
