[hypoxia]

Before I would do anything, I need to determine if this thing has anything left in the system and if not, where it leaked. Not sure if it is economically feasible on something that has long refrigerant hoses going from front to rear. I guess this is a task I would farm out if I were to continue. Would be nice if it worked. I think dash air are the first to go on coaches.

IMHO, if you want to repair the dash air, the only salvageable parts may be the condenser and evaporator.  It's best to replace the compressor, hoses and receiver/dryer.  The price of refrigerant has skyrocketed.  R134a is on the way out and the new R1234 is very expensive.  Stock up on refrigerant if you plan to repair and maintain the system.  The green new deal will make refrigerant extremely expensive in the future.

At the end of the day you could probably run the generator and roof air for years and be ahead financially.