For a typical Phoenix Cruiser (with no solar) boondocking is not a science project. There are some basic practices to extend your bookdocking independence.
ABOUT YOUR QUESTION WITH THE REFRIGERATOR
Set your refrigerator for propane. For Irene and I, we mostly boondock so we set it there and leave it that way for our entire trip. The fridge in this setting uses both propane and 12V electricity to operate so there is NEVER a reason to turn off our 12V electricity when on a trip. I place a Post-It note over the 12V kill-all switch by the entry door as a reminder to leave it alone. Surprisingly, the fridge uses small amounts of propane and 12V electricity to operate, so don't worry about it's energy drain on your batteries or emptying out your propane tank. If we don't use our furnace, we can go 3 weeks without refilling our propane tank.....the fridge uses that little.
About the whole house inverter. Keeping it off during boondocking saves a lot of battery power. When boondocking, we utilize the inverter only to watch TV.
I am the power-management guy on our trips. When camped for days at a time without driving the motor home, I run the generator 1 to 1.5 hours each morning to maintain the two batteries. I use a more powerful secondary battery charger to maximize the generator run time. But you can use the on-board system. Just be sure to turn on the inverter/converter when the generator is running. Missing recharging just one morning will sometimes create a power deficiency the following day, especially if we were very active in the RV the evening prior. While the generator is running, it is then that we make full use of 110V like making coffee, run the microwave for breakfast, use a hair dryer, etc.
We enjoy camping in the fall to avoid summer heat and crowds, so we rarely use the a/c. The sun sets earlier in the fall so in the evenings we often watch a DVD movie, read, or play a game of Scrabble together. Having an active home for many evening hours is the reason why I run the generator most mornings when boondocking.
If using good power management practices, boondocking ends for two other primary reasons.
1) Your 55 gallon fuel tank is low preventing the use of the generator
2) You ran out of fresh water.
For us, it's always about the fresh and waste water. When possible, we boondock near an RV dump station, I drive over, take care of things, and get right back to the camp site.
As always, before extended boondocking, make sure your gas tank is full, your propane is adequate, you have a full tank of fresh water, and your food and drink is all good.....and take your showers just prior to visiting the RV dump station so you don't consume large amounts of fresh water so quickly.