Once your spouse gets a job as a NP-how much time do you realistically think you will have to use an RV?
Reliable internet will be important. From my experience you should not rely on a campground connection. Cable to a house or apartment is much more reliable and has faster speeds.
I have a friend doing a NP program on line here in NM. She needs quiet, uninterrupted time, and desk space. I am not sure if even a large 5er will have a quiet, stable, work space free of distractions, especially if you are trying to cook a meal, tend to dogs, etc while she is trying to study/concentrate.
Buy a house. If you loose some on the resale, it will not be as much as you will loose on the resale of a big 5er and truck.
One more thought: Do not limit your job search. Look into State Department/UN/Overseas construction company (Haliburton/Brown&Root/etc) positions overseas. State Dept. uses NP in many of the embassies and the pay, benefits, life style is great. I was on embassy duty, and while some places are harder than others, they are all pretty good living. UN and Construction Companies can give great pay but some of the locales are remote.