Well see, those are things I am not aware of. That is why I would like to see somebody take this idea and make it more functional.
My only desire here is to be able to have multiple power options, like a big RV does. If shore power is available, great, then both 12v and 120v applainces can run off of that. If it is not available, I would like to be able to still run everything, at least for a while. I will be running an A/C unit, and possibly a 3-way refrigerator. I am guessing 20 amp breakers would be good to have. Again, I can only speculate. I spent one year as an electrical contractor back in L.A., in the early 80's. I never had to design a system in that time, especially not one like this. Mostly I would put in outlets and swiches where my boss told me to put them.
If you can not do a computer drawing, I urge you to put pencil to paper and then scan it, so I can get a better idea of what to do. This diagram is an improvement over the first one I did, but there are things I am just not knowledgeable enough of to make it 100% right.
I would like to throw in a solar charger for this too, but could not figure it out. I also thought a generator might be good, but if I did something like that, it would be a portable that I could just plug in the the shore power socket, so I would not have to do anything extra there. If I ran a small generator, I would probably mount it in my truck.