Cody Templeton
FRF Addict
Above pics - 2 group 37 lithium ion batteries, 2000 watt inverter, ARB twin with 3 gallon aluminum tank under bed ETC. Many mods since. Hope this gives you a basic Idea. With the bed rail system, anything that fits in the bed can be tied down securely even over the most difficult terrain. I used 1/4 - 20 stainless rivet nuts to tie the rail system, ARB, batteries, ETC down.
I'm planning on doing something similar. I was going to mount a second battery on the frame where the spare used to be along with air compressor and air tank and then mount the inverter behind the driver rear seat. Trying to keep my bed clear as I use it quite a bit to haul things. Nice setup!