Generator and dimming lights

Just bought new Rpod 171. I know zero about electrical stuff but totally willing to learn!!

What Stephen said is right good. 

There are two types of power our campers will use. 12V DC (from the battery and from the converter powered by.. ) and 120V AC. 

The 12V DC system powers the lights, the thermostat, the control circuitry for the fridge, the water pump, and the control circuitry for the water heater. These are all very low power items, drawing in the single to double digit power range in watts. 

The AC, by comparison, uses 1670W. The microwave is probably around 1200W while running. I'm not sure how much the water heater electric element draws, but it's probably several hundred watts. 

So if you want a generator, what do you want to run off of the generator? If you want to run your AC, you're gonna need a generator that supports at least ~1700W output AND you want to consider that the AC compressor requires a large amount of current to start. Stephen mentioned the Easy Start, which is a device installed and wired into the AC unit that reduces the startup power demand of the compressor by more slowly starting it, rather than it trying to start 'all at once'. It works wonders and allows you to use a smaller generator and not overload it when the AC starts.

Note that if you're running the AC, you won't be able to run your microwave at the same time. 

If you step up to something like the Predator 3500W generator (which BTW has a great reputation, I'm probably going to get one myself), you could probably run the microwave and AC at the same time. 

For the fridge, IMHO, the best way to run it is off of LP, unless you are at a campsite or location with a 30A connection. Then I'd run it off of AC. Running off of battery will suck a battery dry in a few hours. Draining a 12V lead acid battery too low can destroy it (it won't explode or anything, but it may lose its ability to recharge or hold a charge). 

Cariefields - one thing to add to the mix. If you don't need to power items that require a generator or 120v electrical power (like microwave and air conditioner), then you might consider solar. I have a single 12v battery and most of the time we camp where electricity is not available, and a simple 100w solar panel system keeps my battery charged up. My main needs are lights, occasional heater use (primarily propane is used for heat but the battery powers the fan), and water pump. A self-contained solar system costs around $2-300. It just plugs into the side of the rPod (you should see a plug next to your door that says "solar-ready".