Why does your wife want a motorized RV in this situation? Are there any plans to travel with it, or just to use it while it is sitting in one location?
If you're looking for a vacation home, an actual house trailer (of the trailer park variety) would probably be much more satisfactory than most any RV. It would require less maintenance and have more room and quite possibly be better insulated. It would, of course, require water and sewer and electricity at the property, which may make it not an option. Among RVs, a towable is probably more suitable for a fixed or semi-fixed abode than a motorhome, if only because your money and room is all devoted to living space stuff and not split between living space and drivetrain.
A class B RV is basically a conversion van—a (nice) cargo van with some living quarters built into it. Since cargo vans are comparatively small, this means a lot of inherent compromises: small holding tanks, tight quarters, little kitchen areas, beds that may need to be converted to couches or whatever during the day, that sort of thing. They're much more satisfactory for travel than for staying in one location long-term.
A class A RV is larger and usually more suitable for longer-term stays, but less suitable for day-to-day driving. A class C is more similar to a class A than a class B in terms of space, generally speaking, though there is a range. (The difference between the classes technically only depends on what sort of a chassis the unit was built using. A class A uses a bare chassis, a class B a van, and a class C a chassis cab or cutaway chassis. Bus conversions are usually lumped with class A's, for better or worse.)
Any RV requires a good bit of maintenance, and a motorized RV requires more maintenance than a towable because it is both a house and a vehicle. Sitting for long periods—many months—without use or driving is generally not great for a motorhome. If it is to be driven at all, there are tires and drivetrain maintenance and registration and insurance and other similar details to attend to.
