I want to install a small inverter on the sink cabinet wall as you enter the coach. I would drill a hole in the floor at the base of the cabinet and one into the metal battery compartment, wiring into the batteries.
Would drilling hole in the coach and wiring the inverter have any consequences for the warranty?
I did that (and much more) in both my Vegas and Axis. I do not think you will have an issue unless you miswire and blow something in the process or if you drill into something. An inverter wired directly to the batteries should not affect anything else, if it is wired correctly. Make sure you put a fuse for it close to the battery.