"Are there any suitable propane fittings that would be safe to use and
> quick to connect/disconnect?"

Yes. The propane hose going to my catalytic, mounted on the battery bulkhead
behind the psgr seat, is a removable quick release fitting hose that goes
from the bottom of the sink cabinet. The hose could be any length and since
it's rubber it can be bent in any direction to snap/plug into the heater.
Mine goes along the floor in that seam between the floor and bulkhead.

By the way, I notice the heater in the pic is mounted in the table bracket.
If you like you can apply that same bracket to the psgr seat bulkhead so
that application can be used over there. It occurs to me that Terry K's
foot-step device could be used and modified to mount the heater on. His foot
step slips into the front table mount to help volks get into the upper bunk.

bob