FYI Harbor Freight has their 1000 watt inverter on sale until the 23rd, at least where I am. I picked one up since my 400 watt just wasnt cutting it for my three amps and interior lights and surging it with an occasional blender. The 1000 watt will surely be enough but if you want the bigger one go right ahead.
Presently for my battery bank I am using three different brand regular car batteries hooked up together utilizing a battery isolator. Quite frankly the battery isolator was a breeze to hook up to the alternator, house, and starter battery. I know its not the ideal setup but I had the batteries setting around. I can tailgate all day and run the stereo loud, lights in the evening, a tv, and the blender and have never had the low voltage alarm go off on the inverter. The alternator that came on my 1984 Bluebird Ford B700 gasser was a 160 amp that i had rebuilt. Some french sounding name or something.... Most busses I believe come with at least a 120 amp or greater alternator.
If your bus is good mechanically and your not worried about your tires I would spend money on making any part of the trip more comfy.
--Buy a shower curtain and a camping porta potty and set it up in a corner of the bus.
--Change out the bus seat for a captains seat from a van or something.
--While your at Harbor Freight buy one of their battery powered racket ball racket looking bug zappers (on sale now also), very handy for all those pesky bugs that wont stay out.
--Consider making some screens that you can put in windows that are down to keep those pesky bugs out.
--Buy some matchstick style roll down blinds and put them up so you can keep unwanted light out.
--A 15' x 15' tarp attached with some eyebolts or such on one side of the bus and poles under the other side staked down with rope makes for a great make shift awning to lounge under on a budget.
--find someone that can give you some carpet remnants to make the floor much more comfy for the trip.
--always carry tools to do easy fixes on the fly...extra belts, hoses, hose clamps, duct tape
--buy one of those back up bulbs with the beeper in it !!! safety first while camping !!
--couple of lengths of 2x10 in case where you camp isnt totally level (I didnt have them one trip and felt like i was walking crooked after the weekend lol)
--another good thing to carry with is a couple of tire chucks to use just in case your sleeping and the kids pull the brake, you never know...
Ok, Im rambling with useless ideas.... must have been the empty beer cans
Maybe when Im sober I can think of some usefull ideas.
Have fun on your trip !!!
TonyC in Iowa