I'm wondering about scissor Jack's aka trailer levelers
Welded n place, use a cordless drill with socket to run them down for leveling, and back up for storage, just like on TT bumpers and frames
A pin thru the jack stops it from opening while moving
In the RV catalogs they call them stabilizers
The van probably came with this type of jack and has places on the chassis were to be used when changing a tire
A trip to the recycle yard might find four of these really cheap
Then weld in place, drill hole for latch pin or maybe some dog chain with snap hooks for keeping in the retracted position