I had seen this kind of thing done with just awnings at Quartzsite, AZ. Two 19' Escapes parked curb-side-to-curb-side just far enough apart that their extended awnings touched in the middle. And a 17'
Casita Liberty pulled up at one end so that its extended
awning touched both Escapes' extended awnings, creating a large covered area between the 3 trailers. Now they weren't connected in any way so the rain dripped in the middle, but it wasn't bad.