Another big part of the puzzle is where you are going to install everything, and will the items fit where you want to put them. If you want 100ah of battery, it’s probably pretty easy. If you want 200ah, you may have a puzzle to solve. I would have liked to install two Battleborn batteries, but there was no way they were going to fit in my battery compartment with the chargers with adequate space for charger cooling and easy access to wiring. Luckily I found a different battery option that fit well and I’m happy with.
I would start by getting accurate battery compartment dimensions and begin trying to lay it out on paper. I had mine all mocked up and ready to install when I received the camper, so installation was fast. It gave me something to work on while I waited as well.