5000 BTU A/C unit finally fitted into the nose. Here is the floor cut out for the exhaust. Right side intake air currently remains a 4" opening, but the left side has been upgraded to an 8" opening. All Fwd hot exhaust areas have been lined with aluminum and insulated. And, of course, the interior cold side and the exterior hot side has a full separation wall and things are insulated accordingly to keep the heat out of the trailer. It is not 100% efficient until I install a duct out the front into and thru the tongue box. For now I am forcing air into the condensor to help overcome the small under trailer exit.