Just FYI -
I had seen many other window AC mounts that didn't include a platform or pool-noodle/pipe-foam padding.
My own design objectives for the window AC mount were to:
1) avoid damaging the window track or butyl(?) window framing sealant
2) avoid any gelcoat damage by hard surface (plywood) vibrational rubbing
3) avoid breaking/damaging window glass/screen during AC lift/install
4) avoid rainwater
leaks or bug entrance into the trailer
The platform that the AC sits on is 16"x16" plywood (1/2" thick)
(see one final attached pic.)
I imagine that my design could still be improved but it seems to meet above objectives.
Best of luck to all!
Ray