It sounds like the AC is up for a good going over. First thought is that the incoming and outgoing air are being allowed to mix, and the blower is just blowing air around. You'll need to drop the inside part of the AC and identify the intake and outlet areas, and see if there's a missing baffle or something?
On the outside, you need to pull the cover and look for leaves, nests, etc that might keep air from circulating around the condenser?
1997 37' HR Endeavor, 275hp Cat, Freightliner
03 CR-V Blue Ox, Ready Brake