I fitted an Outback Roof console, ABR dual battery tray and wired up a Century Deep Cycle with a Redarc SBI12 solenoid.
I have a fuse box under the passenger dash for future accessories that's now hooked to the AUX and switched with the ignition through a relay. All new accessories (UHF, GPS, etc) will run off the AUX battery and the constant line to the rear for a fridge and lighting is now hooked to it as well.