The installation requirements of your inverter will determine the circuit breaker required.

Remember, you could be transfering or inverting up to 30 amps, plus you need additional input power to handle the battery charging and that could draw as much as 20 amps.

On my current coach each inverter is on a 50 amp circuit. The output is 2500 watts. Wires are sized appropriately. The actual wiring is not complex, but getting new wires where they need to go could be involved because you are not replacing a component, you are actually adding one.

I added a 12 CD pllayer to my coach last year and I wanted it to look like it was installed from new. To run the wires with the other wire bundles was a pain and that took more time than anything because I had to disassemble so much.

What you want to do can be done, and the ease with which you do it depends on how easy it is to run the wiring you need.