At our home we have two large paintings hung with a type of heavy duty hangar that might work for the walk thru module. Might not.
This type of hangar consists of two long rectangular sections. Look kinda like aluminum rulers. One section, the wall part, has a female groove facing upward and running the length of the section. The second section, the painting part, has a male edge facing downward and running the length of the section.
The painting is placed against the wall slightly above the female hanger and then just slid down slightly until the two parts connect. Makes for a very secure mounting.
In a similar manner, the grooved female part could be added to the fixed part of the module and the male part to the swing up part. When lowered down a very strong and precise connection is made. The hangar is made of aluminum and has a large number of pre-drilled countersink holes so it could be securely mounted and being aluminum would hold up to the rigors of use.
The only concern is the combined width of the two pieces. About the width of a couple of rulers. If width is an issue the tracks could just be made longer. Even if the gap between the two module parts were a little wider it wouldn't matter because the two modules would be very securely fastened by the action of the device.
As for lateral motion. A blocking device like a screw can be placed just outside both ends of the female section so the parts don't slide sideways in the groove. This could be done in a manner to make a tight fit or to provide some lateral slack which we seem to usually need due to tinplate track and module wood expanding and retracting with temperature and humidity.
We could then just leave the latches on the top so the bridge isn't accidentally lifted.
These hangars come in a variety of lengths. 6 to 24 inches I think. You can see them at Lowes or Home Depot and maybe Michaels.
I have a couple that I could bring to the workday but I will be in the San Francisco area at O Scale West that day and can't attend. Rick or whoever is welcome to drop by and pick them up so you can see them.
A better idea might be to go to the stores to see the variety available to see if one of them might work better than another -- or if at all.
For what it's worth, I REALLY missed the Walk Thru module at San Antonio and really appreciate that Scott and (I think) Adrian built it for us. So, good luck in improving it. I'm hoping it will be available for New Braunfels. Bet other less agile guys are hoping, too. Besides, I feel it's demeaning for an elderly gentleman to be seen crawling around on the floor like a toddler -- even if life does go full circle!
Bill