What's the best way to vent a toilet / shower compartment? Electric fan/vent? Advice on which fan/vent [manufacturer?]? I'm assuming that the compartment door will seal the compartment.
You might do some searching on Airstream forums. They have a really effective bathroom vent (same one probably since the 60s/70s)
It vents straight through the floor, opens a flap when turned on IIRC.