Specs for electrical infrastructure & gear appreciated

Still kicking the tires. I have a black hole of information regarding specs for electrical to run stuff in the van

The goal is to be at least two days in the middle of nowhere, running off the self-contained grid. Not sure about solar yet because I'm leaning towards a roof rack that I can stand on to use as photography platform.

How do I select batteries; and associated supporting gear to power the list below

Minimum equipment:

Microwave - on demand use only
Cube fridge/freezer - on all the time during trips
computer - ~3 hours per day (edit photos)
heater - on demand

still in the maybe group

TV
Sat dish/rcvr
A/C

Thanks