Adding batteries, inverter and solar into truck camper

I would rule out using your HW heater or a ceramic heater off battery/solar right now. You would need a huge battery bank and mega solar for that. Otherwise 200-400w of solar and 2 good batts will keep all your lights, pump, furnace and the 12v fridge circuits running just fine as well as charging laptops/phones etc. HW heater and fridge on LP and your generator for microwave or other short term high amperage items.

Search for "members solar install" on here, lots of great threads to inspire your build.

daryll