The two batteries mentioned in the previous post were mounted on the tongue and wired in parallel with AWG 1/0 welding cable. The inverter is wired with a 500 amp fuse between the battery bank and the inverter, and I added a master shutoff switch between the battery bank and inverter. On the 110V AC side, the HVAC was wired into the primary output and is the only thing on that circuit. The cooking and electricity in the trailer is all run from a separate GFI protected plug.
I then dropped the whole assembly into a plastic toolbox made for the back of a pickup. This assembly is mounted on the tongue above the HVAC unit.