Jim, how long is your Airstream? 21' 8"? More specifically, what's the distance from your X charge port to the rear of your trailer bumper?
It sounds like you may be thinking of parking parallel to the row of charging stations, which I agree would be the only feasible option in this location. Parking your X nose-in would block the aisle with your trailer. I assume your X has its charge port on the driver side? If it were me, I'd park with my trailer alongside the enclosure, with my charge port alongside the charging station closest to the enclosure. The nose of your X would only block the stall you are using and the stall next to that. It's not as if all 8 stalls are likely to be swarmed. (Or at least not before Model 3 arrives.) There is some room (about two parking spaces worth) beyond the stall the other end, before the access from the street, but I can't imagine that the charging cable would reach around the rear of your X. And there will probably be ICE cars parked in those spots that your trailer would block.
I'll be up there in the next few days. I'd be happy to take my long measuring tape with me. They might even have it striped by then, so I can see how close the adjacent ICE parking will be. We haul an Airstream around, too- but with an old diesel pickup (B99 biodiesel whenever possible). More than a little jealous of your rig.