On my Arctic Fox 1150 there wasn’t a good place to relocate the battery from the factory enclosed battery compartment accessed from an exterior door.
My new lithium battery was too long for the OEM compartment. I used an oscillating tool to open up the OEM ABS battery box. I also created a new wood tray to stabilize the new battery.
Opening up the OEM battery compartment not only provided room for the new lithium battery but also allowed for the new battery to now be on the warm side which keeps the battery from freezing while in use.
This also allowed the inverter to be installed within the required distance from the battery. IIRC Xantrex required the inverter to be no more than five feet and it took exactly five feet of cable to reach the inverter.
This also allowed me to use the existing DC cable to the DC fuse box thus avoiding a rewire for the DC power.
Be sure to check, double check and check again to make sure you are using the proper size electrical cable for any of your required electrical runs. There are a number of online sites that have wiring calculators.