I've got about 10 days of overnights in the cabin now; just tagged my buck, so probably only a couple more nights this year to get a doe during gun with my son.
Lots of learnings. First couple nights, left the inverter on overnight to keep cell phone charged and run cell booster. Well, for whatever reason the booster worked awesome in the summer but not now. Kinda a waste, helps with texts but not internet data or voice. Might have to investigate and re-aim the antenna. Basically leaving the inverter on overnight burns 15-20% of the battery (can only run down to 50% technically). So I learned to bring external cell phone battery chargers, charge them up in the day, so I could kill the inverter completely overnight.
Now I'm in a place where I can run the microwave 5min a day (each min is 1% battery), make a couple cups of coffee in a Keurig, watch some TV with the antenna booster on, run one of the two light fixtures, and I only use 10-15% per day. Installed some battery powered tap lights to enable bathroom breaks etc with inverter off at night. So I can EASILY get 2 days off batteries, 3 if I am a little careful. If it's sunny out at all I'm up to 100% again by 2pm even with the low falll sun.
11K BTU furnace works pretty well, doesn't take any electricity. It's gotten down to high 20s last couple nights, kept the setting low and still didn't need heavy blankets. Regular propane tank on about 7-8 nights, just now getting low. Insulation seems pretty good.
The water system is a nice bonus, able to fill the camp toilet and wash dishes. Weather is warming up a bit so I think I will make it into the opening weekend of gun season before I have to winterize it.