We are about 13'3" as well, but it depends on your tow vehicle.
A/C-I have not had that issue, but I did notice that the bolts weren't very tight while checking everything out. I tightened them but I only snugged them.... if you tighten them too much you will "sink" the unit into the roof and condensate will not drain away.
What will help is moving more air through the unit. Even though it has a low speed I only use high when on a/c, and I leave the fan running in the on position, this will also dry and warm the coil after the unit has clicked off. It also keeps air flowing and keeps it a more even temp in the trailer.
