First suggestion... Do a Search on the forum for other modifications & Fixes to the A/C.
Second suggestion is to have Hubby get a ladder... yeah I'm height Challenged... and open the grill below the A/C unit. there are two covers over the screws in the grill... other screws are in the intake side above the filter.
Once he's got the plastic grill off... using a flash light... look for the sheet metal divider wall that separates the air coming into the A/C... from the Cold Air flowing out of the A/C unit. This sheet metal wall is all that prevents the Cold air from being pulled right back into the Return air side of the unit.
The sheet metal divider is held in place with double side tape... this tape can lose it's holding strength and allow the sheet metal wall to slip down... and allow the air to circulate inside the Unit... this, along with a humid condition where your parked.. can create a risk of the Condensation Coil to freeze up.
While your looking up there... be sure the small sensor that detects freeze up conditions... is in place on the Condenser coil. It has 2 wires and it clips on the upper center of the condenser.
If you've found the Sheet metal has a gap that is allowing circulation of the Cold A/C air... use the foil tape to seal the 2 sides of the A/C unit... and seal any other areas that could allow the A/C air to flow into the ceiling... such as holes in the frame of the unit. Last... check the foil tape that seals the discharge side of the A/C Cold flow of air that goes into the duct work... smooth any rough edges... this will help the air flowing into the duct work.
Last is the A/C Tent trick... which you should discover once you've did your search on the forum...
Good Luck !!