The harsh reality is that any RV of that age will most likely will require an expenditure equal to the purchase price in the first year to keep it on the road and fully functional. There are rare exceptions, but considering your inexperience you will not know the difference until it is too late.
No offence intended, I am only pointing out what seems to be the obvious to any experienced RVer.
Considering everything involved, my opinion is, you should rent an apartment in close proximity to where the new house is being built and be there every day to watch over the project. Building a home is a monumental project and the ramifications of problems may last for decades.
I am in envy that you have the resources to proceed with such a plan, but I would not attempt it due to some of the above reasons. The idea to go on the road and tour the country to return to a new and perfect home are just not realistic in my opinion.
I genuinely hope other members will chime in with a more optimistic outlook. A full “Pre Delivery” inspection of an RV before purchase should take about four hours to check out all the systems and the entire rig from top to bottom. Take a ladder, creeper, flashlight, multimeter, camera, and lunch.
DO NOT, supply any payment or deposit in advance, that will be the end of your negotiating advantage.
Best of luck.
