Originally Posted by baadpuppy
Tomorrow I'll get out there and measure the frame rail distances on both busses for ya. I think they'll turn out to fall in the 30" to 50" range though. Looks a lot like a standard truck underneath the conventional bus.
The grass is still damp and I'm feeling lazy, so I only measured the rear frame of the conventional style bus. The frame appears to be C channel, and the distance between the narrowest points at the bottom is 24", and between the widest points is 34". Behind the rear axle, there is virtually nothing under there but frame. It is a ladder type frame.
From memory, the frame rails on the pusher are quite similar.
On the conventional, you do have the transmission and driveshaft between the engine and the rear axle which limits what you can do between the frame rails there. There is the fuel tank on one side between the frame rail and the skin (and well protected). There is also the battery compartment on the other side (on mine at least).
On the pusher, you have the entire rear basically being used by engine and driveline with very little room to add anything. Forward of the wheels, between the frame rails, there are all the air lines and power steering lines and throttle and brake linkages, etc etc. Basically, that space isn't really usable, unlike what you might think.
On mine, on the passenger side there is the front door and steps, then the front axle, then the fuel tank, then the undercarriage storage box which is big enough to store a few bodies and will hold my primary house battery bank, then the rear axle area, then the air intake area. On the driver's side, there is the fuse and power distribution panel, then front axle, then big empty space, then an empty battery compartment, then the spare tire bay, then the rear axle, then the chassis battery compartment, then radiator.
The spare tire bay slopes, so isn't really useful as it is for a storage bay, but I plan to make it flat and use it for more storage, or perhaps for a second house battery bank. The secondary battery compartment has a rusted slide in it, and I haven't decided what to use it for yet.
I do plan to have a swamp cooler and an AC compressor under there some where, and it'll probably both be on the street side. The spare tire area might become that instead of a battery bank.
The trailer will be my primary place to store things I need access to from outside. I do plan to have at least one pass-through compartment from the outside to the inside though. I also have to make sure to save room on the street side for shore power/water/sewage hookups.
Anyway, I hope this helps in some way.