Useful Tools and Materials:

There are a few tools and items that are just so useful that they deserve special mention.

There is no substitute for removing your seats. Use a cut-off wheel (not the grinding disk) and slice the heads of the bolts right off. I found that grinding a flat on the side of the bolt head with the grinding disk first made it even easier to cut them off.
Cordless drill. I like a 14 volt drill, its strong enough for most tasks but not as heavy and fatiguing as the 18 volt monsters. Buy a lot of #2 Phillip drivers and don't be shy about throwing them away when they get dull and stop gripping the screws.
There is no cheaper source of angle iron than old bed frames. However, bed frame steel is hard stuff and will eat hack saw blades pretty quickly. Use a cut off saw or power miter box fitted with an abrasive metal cutting wheel.
You'll want a power miter box for wood working too.		I found this Ryobi at the town dump! All I had to do was remove and straighten a bent fence!
I don't like crimp connectors, they always fail on me eventually. I use solder and heat shrink tubing for most of my electrical connections making this butane soldering iron invaluable. I also use it in torch mode for soldering my kerosene lamps.
Polyurethane construction adhesive is liquid duck tape, it will stick anything to anything and will even cure when it's 40 degrees out (albeit slowly). I use this on all of my woodworking and between cabinets, partitions, and paneling where it meets the bus floor and walls.		Yes I said Duck not duct. I'm a traditionalist.
Silicone seal is nearly as useful as the polyurethane. Use it for sealing cracks, waterproofing where you go through walls or the roof with pipes and wires and for patching window gaskets.
Self drilling screws are like nails for metal, you can just bang'em in where you need them. When drilling into the buses ribs go slowly, school bus rib steel is tough and too high a speed will ruin the drill point before you get through.
Dremel tools can be very useful. If you are about to buy one get this one, don't get the new "ergonomic" one, it's reported to be cheaply built.
If you live up North you'll want a heater like this to keep you warm when you are working on the bus in the winter months. This one is 18,000 BTU and works pretty well. Store it in a warm place, mine gets fussy when it's stored in the garage, I think there's moisture in the regulator. Be sure to open a window since this is a "vent-free" heater and needs a source of oxygen - as do you.
This is a Drill Doctor, a drill bit sharpener. While this one isn't strictly necessary, it is so nice to have sharp drills when drilling tough metal like school bus ribs or bed frame angle iron. If you spend your money on lots of drill bits you'll usually have a sharp one handy. But if you spend your money on a drill bit sharpener you will always have one handy.