I've removed my AC unit for repair. It's not a lot of trouble, but it is awkward and a little dangerous because of working in an elevated location.
If you want to try it:
1. Figure out how you are going to safely get onto and off of the roof. Remember you will be carrying the AC unit down, hopefully without damaging it. I suggest building a scaffold so that two people can work at this task. Only walk on the ribs where you can see rivets or you might damage the roof.
2. From inside remove the filters. Then the interior trim. This will give you access to disconnect:
2a. 120v AC wiring (unplug the trailer first)
2b.
12v DC wiring. (disconnect the battery first)
2c. Thermostat wiring
2d. Condensate tube
3. From the inside, remove the bolts and frame that clamp the AC unit to the roof.
4. From the roof:
4a. Remove the screws that hold the AC shroud, remove the shroud and temporarily store it where it will not get damaged.
4b. Lift the ac unit and remove. (carful not to damage trailer or AC)
4c. Place a temporary cover on the opening and secure it, so it will not blow off, critters can't lift, and water tight.
5. Replace the shroud and protect the bottom of the AC during storage so critters can't get in.
When you re-install you will probably need a new foam gasket to get a proper seal.
add edit:
If someone has used a lot of caulk trying to seal a leak, it might not be so easy to lift the AC. There was a TON on mine. It took a lot of cutting and scraping.
I would not remove the AC for storage. Both of my trailer set outside full time.