Got the propane tank mounted......
I ended up mounting it on the passenger side of the van under the barn doors.
The driver's side has very little space with the rear A/C refrigerant lines so it wouldn't be "stealth" enough for my neighborhood since there is not enough width between the frame and body to "retract" the tank. (my van cannot look like an RV parked in the driveway)
I have it mounted such that when it's fully stowed (in the "up" position) I can still reach the valve. It will only need to be "deployed" for refilling.
The mounting frame spans between the frame and the body, so the body side mounting uses rubber washers to allow a bit of movement. There is approximately 1/4" clearance all around for some comfort.
Existing holes in the frame (there are many to choose from!) were used for mounting on the frame side and the body side uses a couple of 1/4-20 screws vertically oriented under the side door step.
The raise/lower mounting works OK.......it takes a lot of turns of the knobs to move the tank vertically......16 turns per inch since the threads are 3/8-16.
I'm using the regulator from Go Westy and some 1/4" OD soft copper to feed the Propex.
The shoulder screws shown are from the parts bin; done correctly all 4 would be the same length.