
Breaking with tradition I have been putting some time actually working on this instead of just thinking about how to do it. The door is a picture frame of white wood 1x4 covered with same polyisoanurate as the box and corner bead trimming the outer edge for abrasion protection.
I used a set of lift off hinges from McMaster Carr

The door was having some issues that my brother in law helped me work out. The box was racking due to flexing. It now has a permanent location. Ultimately I put my old boil kettle in with about 13 gallons of water to hold it down, then we connected it to the garage wall in a couple places to provide the needed stability. If I were starting from scratch I would have make a complete frame and lined it with the insulation.
I'm using 2 rows of this foam tape made of silicone/EPDM blend for the door seal:

Two rows of weather stripping. Two row barley. Coincidence? I think not!
I'll try to post some pics. I need to build a cowling for the AC unit, then a test....