Came across a forum thread that is relevant to my AC issue: Experiences with Carrier Air V installation? - Airstream Forums
I had tried tightening the mounting bolts to compress the gasket further, but that didn't seem to help before I pulled everything apart. I noticed that when tightening the bolts that the control panel was getting rather snug against the roof, and when I put the cover back on, only one screw would tighten. Apparently the stock screws are on the short side, looks like when I'm ready to reinstall everything I'll need to pick up new screws, which is just as well since the heads on two of them were a bit stripped anyway.