Shower adds some design concerns that may impact what kind of bus you choose. In a (school) bus, headroom can be in limited supply. Know that you'll not only want enough room to stand, but for the shower head to clear your head.
I recently posted how I built my shower:
I have ample room to stand and for the shower head to clear my head.
- The shower is located in / doubles as the hallway- at the apex of the roof. If it were at either wall, the shower head wouldn't clear my head. Now one can build a shower up against the wall and clear your head if the shower head is located on the wall closest to the middle of the bus and you are careful to keep it at the peak.
- Another possibility to solving the headroom problem is to cut into the floor and put in a lowered section where one can step down into the shower.
- Make room for lots of fresh water storage- we have 70+ gallons, and even then water goes quick when taking showers. We are using a low flow head (0.5 - 1.5GPM) and a valve on the shower want to slow down usage.
Alternatives to carrying lots of water- relying on being connected to a fresh water supply is an option. You could also consider building a shower water recycling/filtration system, which is not trivial.
Consider (when making your layout) putting your sink in the shower or on the same wall as the shower- this way you do not have to run plumbing to multiple places in the rig. If you plan for an RV style flush toilet / black tank, colocating all three will greatly simplify things for you. Mind where your tanks are in relation to these!
Showers are much easier done in skoolies with roof raises, city buses, or coaches due to the extra headroom afforded. These all have their sets of drawbacks and challenges.