You might take a look at my re/mod thread ('78 31' Sovereign
) . In post #86 I glossed over the installation.....sure could have done a better job of explaining how it was done. In summary, remove the rear vent, reinforce the area surrounding the vent, be sure to use a good drip pan
, route the drain line down the black tank vent line.
I had previously installed a separate 20 amp 110 volt service for an electric/gas water heater, so I also installed a 110 volt selector switch from an RV junk yard.
You will probably have to trim the rear vent just a bit. The original AS vent had rounded corners.
Most difficult task was getting the new unit up on the roof. Two good ladders and two strong friends willing to work for beer took care of that. Use PLENTY of good sealant - you only get one shot at preventing leaks between the pan and the roof.
The drip pan that I used from AS came with some sort of neoprene that was used to raise the unit off of the drip pan. I positioned the neoprene on the ribs to better support the weight of the AC.
PM me if you require further explanation.