As for a generator, you might get away with connecting a 12V-120V inverter directly to your car battery and running that engine to charge the battery, then cut the engine off while running light appliances. You'd need an extension cord of sufficient capacity of course, and a voltmeter would be very much advised so you're not deep cycling your starter battery. (That kills it.) A $60 800W inverter can do a lot of good.
Heard about that on
Solar1234.com, which (strangely) isn't about solar for the most part, but powering your house during an extended blackout. Some excellent ideas there.
As for how many batteries I'm not experienced enough to tell you for sure, but I do know you need at least one "house" battery that can hold a good charge. The brake system requires it; If it disconnects from your vehicle the battery applies the brakes. So it's a safety requirement. Also if you keep the propane fridge running while driving you need a tiny bit of 12V for the logic board and such. Beyond that, I think house batteries are really only for dry camping/boondocking? Look for true deep cycle batteries, not marine batteries. Again I am not a road warrior so double-check these things.
As for washing and waxing, yes for sure. For ongoing UV protection I was going to have it waxed regularly but I'm still tossing around the idea of having a canopy
such as this.
That model isn't tall enough, so I'd securely bolt on fence pipes to make it taller. Then use some
auger stakes to secure it, and a
used billboard tarp for the sides and additional top protection.
As for the twins, have you considered simply fencing off a section of the RV, then bump-protecting all the sharp corners with
pipe insulation? I don't know what your floorplan looks like, but ours has a front "room" I could easily fence off with one of those
door gates.
2010 Coachmen Mirada 34BH, class A, 34.75' long, GVWR 22,000 lbs.
2005 Fleetwood Resort TNT 25QB, hybrid, 27.5' long, GVWR 6,600 lbs.
God bless!