You shouldn't need to worry about charging the S that much unless you will be making several-hundred-mile side trips. Occasionally plugging in at the RV park (like when you are going for a walk or something) should keep the charge up enough.
If you aren't that familiar with RVs, why don't you rent one for a weekend and go to a nearby RV park?
My son has recently been quite interested in RVs, so we rented a 30 footer at Cruise America and drove about 40 miles to Costanoa, between Half Moon Bay and Santa Cruz. We plugged in, stayed 2 nights, and had most of our meals in the RV. The kids had a blast, but there were some mechanical issues with the unit that made it less fun for me. Another pain was that the RV came empty, and we had to bring all bedding, towels, kitchen, dining stuff, etc.
As for driving, although it was only a 1 hour drive, and I had done it before, it was nerve-wracking, white knuckle driving. So many more things to worry about! Even simple things like lane changes or making turns take some getting used to, as it is so long and wide. I was afraid of hitting bicyclists, parked cars, everything. And all the stuff inside shifts like crazy. Doors pop open, everything makes noise. The carseat for my 3 yr old didn't fit in the dining table forward-facing seat so he sat facing sideways on a couch/bench. The winding mountain road was especially scary: when we rounded a corner to find the traffic stopped and I had to slam on the brakes and everything went flying. Towing a car would be all the more difficult, but plenty of people manage to drive bus sized RVs towing cars, so it's not uncommon, but I think you need experience and practice. And these things get like 10mpg.
For me, I'd prefer to drive the Model S, bring a tent and inflatable mattress and camp at the RV park while the car charges overnight. (@Transl8r, yes I did notice that the power box had 2 outlets, a 14-50 and a 14-30, but it seemed like there were switches for each and only one side was on. Not sure if you can have both on at the same time. Sorry I don't have a picture). AnOutsider, since you have a baby, camping might be a little more difficult. He's still young enough to be on jarred food, but what you are missing is refrigeration for milk (unless he's still nursing then that won't be a problem) and a way to heat things up. It's too bad the model S drive battery doesn't power the 12V outlet, otherwise you could get a little in-car fridge (or even an inverter so you can power a fridge, hot water heater, microwave, etc).
If you want more info on the RV, check out this
detailed orientation video.
