He can boondock forever IF he has way to sufficiently recharge his battery bank. It all depends on how much effort he wants to put into it.
Think of a battery bank as a fuel tank, with electricity being your fuel. If you had a car with a 10 gallon fuel tank and you got 10 miles to a gallon, you could go 100 miles before you had to fill the tank again. If you had a 20 gallon tank, you could go 200 miles. Same thing with your battery bank. You just have to replace the amps you use, and the bigger your battery bank (fuel tank) the longer you can go before you have to refill it.
We have a residential fridge in our bus conversion and just came off a 4 1/2 month dry camping stint. Last year we dry camped 7 months straight.
We have three 8D AGM (glass-mat) batteries (225 amp hours each), an Onan 5500 watt generator, and three 100 watt solar panels. We live the same way dry camping that we do when we are hooked up in an RV park. Last winter while dry camped we published three issues of our RV newspaper, I wrote and published a book, we got up every morning and turned on our internet dish and I worked online most of every day. We also built and installed cabinets in our bus conversion, using power saws and other power tools. Most days we ran our generator between 2 and 3 hours a day, depending on how much sunshine we had to make the solar panels work.
A good quality household stule refrigerator is not terrible on power use. We know many people that have them in bus conversions and dry camp a lot.
For info on our bus conversion, including our battery bank, refrigerator, etc., go to our website at www.gypsyjournal.net
and click the link to Bus Conversion Project.