I hard wired my inverter into a automatic transfer switch that fed into the main power panel. I also ensured at the auto-transfer switch that the fridge and power converter would only be powered by generator/shore power. This requires running a romex wire to back of the camper. I ued outdoor romex in conduit run under the camper. While you are peeling back the coroplast liner, it is a good time to reinforce the bracketry for the water tanks so they don't fall out.
I also upgraded the converter to a Progressive Dynamics one and installed it within 3 feet of the battery banks. This required me to run a Romex line from the power panel to the front of the camper. Having the converter (charger) so close to the battery bank allows for faster charge to supplement solar when sun isn't shining.
A trimetric 2025 or 2030 monitor is a must if you are serious about knowing how well your system performs.
A REMOTE inverter switch is also a good idea. I recommend Samlex PST 1500 or 2000 full sine wave inverter. Commercial grade quality and remote switch shows amperage draw, ac and dc voltage, and other metrics. This inverter allows it to be hard wired.
A PWM or MPPT controller is a decision you will have to make. If you are using a plain 12 volt system with panels wired in parallel than a PWM is cheaper and should work equally or better in most conditions.
If you plan on wiring your solar panels in series for increased voltage which allows smaller diameter wiring from combining box to solar controller, than an MPPT is mandatory.
The risk of series wired solar panels is that shade on one panel wipes out power contribution from all the remaining non-shaded panels. However, a series panel system has advantages that are realized with MPPT controller.
Wire should be sized for less than 1.5% voltage drop. My goal is less than 0.5% voltage drop and I achieved it in my system.
Renogy has good beginner system that are complete with panels, mounts, solar controller, and most of what you need.
Each battery (bank) is switched, power to solar controller is fused and switched, auto transfer switch takes care of ac inverter power.
If you need help, just holler.