I replaced my AC in my 1969 31 foot Sovereign
. There was a guy who came to the house here in KC area. He was listed in the yellow pages as mobile RV repair, I think. It has been probably 8 years. He put in a Coleman AC unit. No it does not connect to the drains like the old one did. It "sweats" its condensation down the outside of the airstream exterior aluminum walls. It works well for us. Don't remember the size of the unit BTU-wise. Overall cost was ~$900. Good luck!