Let me be more specific, the power inverter that I want to install would be mounted and accessible, next to the converter in the camper. I'll run 4 gauge power and ground directly to the batteries for the inverter. Then I'll make a cable from 12/2 with a normal 120V plug at one end, then tie it in somewhere to the utility panel that I showed a picture of. I have a Perko switch between the utility panel battery charger and the batteries, so once it's powered, it won't charge the batteries. I understand the disconnect switch, and will use one of those. I don't, however, want to get into automatic switching if it's a huge cost.
The only 12V power source in this camper thats accessible is inside a cabinet with the TV. There's not enough current there to power this inverter, hence adding one. I intend to trip the unneeded breakers when I power from the inverter that I wire in, so it won't have as much load on it. Another reason for this, is that the TV and receiver is plugged in inside the cabinet also. I really don't want to run an extension cord through the camper to power them.