Our 5er is set up for a 2nd AC unit up front including a 50 amp service and dedicated 20 circuit with 12 ga wire in the ceiling near the front ceiling vent. I'm thinking about installing the 2nd unit ...
How about something like this Domestic 13.5K unit? I'm sure I can probably install this myself.
It's just for the front bunk area so having manual controls is fine. There are round diffusers for the ducted main unit. I can replace the one in the front with an adjustable diffuser that I can shut off when we're running the front unit.