Having said this, I think that the OP should probably just being along a fully charged battery for the uses that he mentioned.

 

My panel is small about 7W and with the load can’t come close to supplying enough power without running the engine/alternator. If I had a larger battery I might be able to go one day and night but that would prevent a battery swap. I’ve opened my refrigerator and it hasn’t been working because the battery is to low and I don’t like that when it happens. I want to park my vehicle all day and not run out of power. I need a 42W panel that can also charge the battery and supply my devices charging needs. Sometimes I need to conserve gas so I turn my Jeep off every time I stop.
I used 8 gauge to wire the controller(it isolates the house battery from the Jeep battery), house battery, and alternator lead. The solar panel (PowerFilm) came with 12 gauge lead. At one time I had the two batteries connected with a solenoid and used spare battery cable to wire the circuit. Plus I have a separate fuse panel for all my auxiliary plugs since it’s an isolated system.
My Jeep is setup for overland, serious 4x4 trails (like the Maze) but not rock crawling. I like to hike, cycle, and fish so this setup works for me.