Herbie,
If you do a lot of dry camping you may want to look into a Gray Water Flush Mod for your Rig - the Mod generally uses the Gray water from the Bathroom to flush the John, not only does it conserve Fresh water but it helps off set the higher gray water use in the bath by moving some of it to the Black tank. I agree on the LED and the Dual Batteries or even Quad 6v as an option would be good. Happy Trails
Kevin