I haven't actually gone to a stereo shop and listened for the right speakers for the bus. I figured I'd start here to see if anyone else has done something they found to be really satisfying. It does sound like the best place to star, right? LOL!
I have 2 new 6x9s in the bottom of the back seat - I think that's a standard in every bus I've seen. I have a power booster that was jammed up into the dash, but it kept falling out, so I disconnected it. I've heard that same back seat compartment is the ideal place to install the booster.
I'll probably end up realizing that the door panel is the best place for the 4" speakers.
Thanks for the input. I appreciate it!