I certainly don't have all the dimensions you'd probably like to compare but I can get you started.
We have a 'dognose' or standard bus with a hood. It's a 65 passenger Blue Bird ('79) and I've got 26 feet from the 'white line' (just at the back of the driver's seat at the top of the entry stairs) to the rear emergency door. The overall length of the bus is about 35' feet.
I just measured a Crown school bus (a single axle 35' model) and it had about 30' from the White Line to the rear of the bus. I suspect that other flat nose (Transit style) school buses with a 35' body would be about the same.
Overall width is about 8' on the outside and depending on the bus' construction (and your interior wall construction) you'll end up with 3" to 4" less on the inside (or thereabouts).
The link to my photo album and to my website are in my signature block below; I have the flooplans I did posted in those locations for ideas. There are also many other floorplans on site here from Vern1, Tullamore, Soused Moose and others. Don't worry about LaPeer's bus unless you want a hot tub