In my experience boondocking, a normal size battery will not last the night with a furnace which is using 7-10 Ah. You need at least a group 27 battery, but to be realistic, you need two six volt golf cart batteries in series, or two 12 volt batteries.
I run the generator for several hours every day, and that will only get me to 90% charge.
My recommendations:
1: If you have not already done so, replace all interior lights with LEDs. This is not for cost savings, but the fact that on average a LED bulb takes 1/7 as much energy for the same brightness. The exception being places where you want some heat, like storage compartments.
2: Get a battery cutoff switch, and disconnect the batteries when not in use. This is a must, as parasitic drains can run your jars dry in less than a week. Don't ask me how I know.
3: Solar is very useful. Were I not planning to trade my TT in, I'd be deploying a good number of panels on top.
4: I like having two different sized generators. One is used for running the A/C, microwave or other stuff. The other is an 800-1000 watt inverter which is used for battery charging, and used because it is very thrifty on gas, as well as very quiet. Of course, one can do the same thing with a pair of Honda 2000 watt models, and just running one or both if needed.
5: Check your RV's converter. If it is a single stage model, chuck it and replace it with a multi-stage, which won't boil your batteries once they are fully charged.
