So my goal with this is to address everything I had wondered about before I got my bus, and detail it simply and clearly online (both here and at our website: juanway.org). There will be more at all major stages including installing bunks, benches, basic plumbing, and getting the bus to run on veggie oil. But we're not there yet. This one is about the first major obstacle - removing the seats.
Step 1: What you'll need
You'll need a ratchet (socket wrench) for the nuts inside the bus.
Where the seats were bolted to the side of the bus, we used a 1/2" socket.
Where the seats were bolted in the center (next to the aisle) we used a 7/16" socket.
There were a couple odd bolts which had probably been replaced by a mechanic after the bus was manufactured, so be ready for that.
Underneath the bus, someone should hold the nut in place with a wrench (7/16" in our case).
Many sites recommend an angle grinder, to just pop the bolts off, and as far as I have seen that works, but if you have the man power, the ratchet/wrench combo is pretty easy, and several people can work at once. Also, more people are likely to have those than an angle grinder.