Before you decide on type of RV, I'd recommend deciding how much room you are going to need/want in it. Being used to a small space, you may not need the same amount of space others recommend. If your wife doesn't want to join you, you may find a smaller rig works better for you. There are plenty of folks out there full-timing in RVs under 24ft and are quite happy doing it.
There are a few places that won't let you camp with a popup tent. In those places, you can often camp with a hybrid BUT you have to "turtle" it (you can't use the popup/popout portion).
Traveling - Labor Day to Memorial Day will be less crowded in many places and more crowded in others (check out Quartzite). Just depends on location, weather, common visitor type, etc.
Rather than buying a house in a location to fit your "off season", I would recommend buying a house in a location that you'd enjoy in any time of year. You never know if after a few months, something happens and you can't travel anymore - you don't want to end up miserable because you're living in an oven or freezing your a## off.
That way, you could vary your travel period also. Summer & Fall one year to visit much of Canada and Northern US; Winter for southern locations; Spring for west coast; etc. If you decide 6 months is longer than you want to be gone at one time, you could do 3-4 month trips with 1-2 months at home in between (might be nice if there are grandkids around, etc.).