If you leave the windows shut, keep the AC on using high fan, and do not try and drive the temp down too low so that the air units get a chance to cycle on and off a bit eventually as they lower the inside humidity this dripping should stop. I have not found any way to eliminate it when the humidity in the coach is very high, just the nature of the restricted intake air flow in our ducted systems, and very high humidity. Once you have managed to get the humidity down and keep it there you should be OK. It may help to find the temperature setting in the back air unit that allows it to cycle on and off intermittently while letting the front one run more continuously. We never had the dripping out of the front unit and that seems to be the case for most of us that have had this issue.
I had read that one Marquis owner had cut away some material that restricted the air inlet area above the inlet filter grate and it seemed to help out some but I do not know exactly what was cut away.
Later Ed