Would this set-up for and AC work?

The AC unit says it has to have "Window opening minimum height (in.) 12.5"

So would that vent be sufficient in my original post or could I even get by with this vent that doesn't open:
www.vintagetrailersupply.com/Service_Vent_p/vts-955.htm

Just make sure that all your vents in the walls and closet are of at least the same area as the corresponding vents on the unit (and subtract the area of any louvers). If it has to suck or blow air through smaller vents it will have to work harder, use more juice, and heat up.

Neo, it depends on the weight rating of the slides. All the slides I've looked at have weight ratings, and if they sell them online the specs might be right on the website. You do want to make sure that the walls they are attached to are rigid enough not to allow them to spread and pull the slides far enough apart for the whole thing to drop out of the tracks. As for the drain, I guess it depends on how quickly the water stops dripping after you shut it off. I suspect that the innards stay cool enough to condense humid air for a little while after shutdown. So without a drain tube, you'd either have to shut it off far ahead enough of leaving to let it all drip out before you push it back into the camper, or make it waterproof underneath so that you can just wipe up the residual drips at your next stop.

You will need to make a metal box to go from the back of the AC unit to the vent. Seal it so all exhausted air is forced out the vent.

New window AC units are designed to blow the moisture out the back with the hot air. They only drip in extreme hot weather. I live in GA and learned this the hard way a few years ago. So you need to seal the hot humid exhausted air out the back from getting to any wood.

Also be advised.
Look at pic above of the vented door from VTS.
Under the lock/latch on the door the frame jamb is solid but has two cutouts one on each side, about 2" long each.
I should know.
Gingersnap ordered one and drop shipped it here.
VTS had no explination as to why it has the two cutouts.
Pretty dumb if you ask me.
It's two places where water will leak into the camper unless you seal them somehow, especially if your not sitting level during rain or if hard rain blowing on the curb side of the trailer. (where her old fridge vent used to be)
Like one way to fix would be to epoxy old trailer skin behind the door jamb on the inside of trailer jamb face, then use gutter sealer on the outside face of the jamb to keep water from running in. The cut outs are level to the inside cut of the frame jamb so water laying in the bottom lip just poors into the camper through those two cutouts!