A Panasonic Inverter microwave oven would be helpful in getting the most out of a marginally sufficient inverter and battery setup. These microwaves, unlike pretty much every other one on the market, will constantly use less power on lower settings (as opposed to cycling on and off at full power). They're also somewhat more efficient and work better with an MSW inverter than a traditional microwave design.
The difference, by the way, is in the high voltage power supply for the magnetron. The usual microwave ovens use, as I understand things, a 60 Hz high-voltage transformer and a voltage doubler circuit. The inverter ovens have a high-voltage switching power supply.
However, I would really suggest trying to do your cooking using the propane cooktop (and propane oven, if you have one) rather than the microwave and electric toaster when you're not plugged into shore power and can't or don't want to run a generator. There are stovetop toaster gizmos available that work pretty well (
this is a rather clever, fancy, and somewhat expensive version), or you can heat waffles in a frypan or even, with care, directly a few inches above the burner flame. Many leftovers can be reheated in a saucepan or frypan, or easily turned into some dish that can be made quickly that way by adding a sauce or incorporating into a stir-fry.
Even popcorn in a saucepan with a lid is not hard and fairly quick, about as fast as in a microwave: a little oil, enough so the kernels shift around easily, the popcorn, and cover and shake gently for a couple of minutes over high heat. It may take a time or two to figure out how much popcorn to start with, etc. Some say to preheat the oil, but I never do and it seems to work out just fine for me.
