Re the generator it depends on what you want to run from it. If you want to run the air conditioner you will either need something around 3KW or higher in order to get the a/c  started reliably or a  2kW plus an easystart soft start system for the a/c. If you just want to use it to recharge the battery then a small 1-2kw genny will work. 

Note that most campgrounds don't allow generator use at night. 

Another important consideration is weight. A 2kW weighs about 50lb. A 3kw about 100. So, you need to consider where you are keeping the generator and how you're moving it around. 

Another consideration is fuel. Most generators  run on gasoline but you can also get propane ones. 

At low power levels, inverter generators run quieter than non inverter ones. At full load there isn't a lot of difference.

There is no one right choice for everyone. My personal choice out of the above considerations ended up being a Honda 2KW inverter generator running on propane plus an easystart for the a/c. 

if your power needs are pretty low (no a/c or microwave) you could also consider using solar. 

I recently purchased a Firman dual-fuel generator from Costco.  https://www.costco.com/firman-2900w-running--3200w-peak-electric-start-gasoline-or-propane-fuel-powered-inverter-generator-gas-and-lp.product.100481637.html - https://www.costco.com/firman-2900w-running--3200w-peak-electric-start-gasoline-or-propane-fuel-powered-inverter-generator-gas-and-lp.product.100481637.html

I broke it in on propane and unless there is no other choice (e.g. out of propane and need to do so) will only run it on propane. It is heavy, but is relatively quiet, not quite as much as a Honda, but a whole lot less expensive. It will start the AC, but I do have an EasyStart installed from when I was using an Generac iX2000.

If all you want to do is charge batteries, you could get a DC to DC charger and, provided you put a battery isolator and run a dedicated line from the tow vehicle battery to the charger. use your tow vehicle to charge the battery when you do not have shore power available. Renogy sells a 20A and a 40A DC to DC charger. The 40A version would be provide almost as much charging power as the WFCO converter. I have the 20A installed in my RPod and the dedicated circuit wired from my Frontier (see my mods) for my LiFePO4 battery and it works well. I can both charge the battery and run the refrigerator on DC while driving.

Now, if you are looking for backup power for your house in addition to camping use, I think you would be happier with something like the Firman or other 3000W generator. Anything less would be questionable for backup power for your house. Even the 3000W model will keep your refrigerator and/or freezer going and provide for some lighting, but don't count on it to run your house's AC unit. You would need more like a 10KW unit for that.

Please tell us more of what you want to do with it. That makes a big difference on what you will need.

StephenH, I would be a bit cautious about running a 40A dc/dc for a long time on an alternator on an engine idling in a campground. Alt current ratings are based at a fairly high rpm (I forget what atm) and drop a lot at idle. Also they don't get near as much cooling at idle, plus they still have to run all the TV house loads (electric fan, engine electrics, etc). Not saying any particular alt in an particular vehicle will or won't do it, just that I'd want to research it and do a test first, run it awhile at full idle load and check voltages and alt winding temps with an ir thermometer.