Amy, I have a 2000btu version of the petcool. I plan on stowing mine and placing it on the ground outside when I camp. That way I can leave it at home when its not needed. This is kindw wordy, I'll post pics in my album soon, but my duct scheme goes like this.
Attach a piece of "veranda" board on the front of the a/c unit with two holes cut for the vents. I used construction calk to attach it-all of this is waterproof.
Go to Woodcraft either locally or .com and get 2 1/2 inch dust collection fittings and hose.
Attach two fittings to the veranda material. Hoses need to have hose ends installed-they will then slip onto the front of the petcool.
Inside the cabin place two plastic blank electrical boxes that have been drilled front and back with a 2 1/2 hole saw, inside the box needs to have another collector fitting.
Cut 2 1/2 holes in the wall and mount boxes over those holes. Cover the outside of the wall holes with two 50amp electrical covers (waterproof) They have to be bored slightly with the 2 1/2 in hole saw, a drill press comes in handy here.
Then you can simply plug everything in when you get there and everything stays dry. Its all worked in testing so far. A real setup and camp test is yet to come.
MC