Started this project on Monday, finished last night. Installed a Fantastic vent cover over the Fantastic vent. If you have the clamp style fantastic vent, email or call them and they will send out the instructions, which are extremely easy. Just some measurements and drill four holes into the vent trim, and install four screws, then the cover.
The Maxxair, I can see is not usually a problem, but being the location of the vent in regard to the top of the roof, makes it a little difficult, but the biggest problem was the plastic vent cover that cover the vent from the factory, it snapped into two pieces when raising for the Maxxair install. Seems those covers don't like UV, and after 2.5 years in Moab, the sun did a job on it. (So. might want to do a check of yours if over a few years old and has been subjected to some high UV rays.)
So, with the roof down and trailer all locked up, I was able to install the fantastic vent cover, then when I started on the other vent cover, I was able to raise the cover up from stretching and reaching inside to turn the handle. It went up about half way, and they I heard the cracking sound of plastic.
So back outside on the ladder and it was broken in to and when taking hold pieces started to just break off. A quick trip to the RV place up the street, and a new cover is in my hands. But getting late, so I left it for another day.
Next day, I found out that you have to raise the roof, and completely disassemble the vent from inside, to remove the arm that the cover's metal channel slides on. So up goes the roof; disassemble the vent, the lower the roof so I can gain access to the roof.
(I was not sure if I should lay the top of a ladder against the top of the raised roof; the lateral force might not have been good for the posts...not sure.)
So, once back on top, it took a minute or two to figure out how to install a new cover. Won't go into detail, but it was fun. Then once it was installed. I installed the Maxxair, which for the right side of the trailer, the hinge side, was a bit of a stretch too. But the clip side (left) was easy and quick.
Then raise everything up and install the rest of the vent parts such as the tighten the arm controller bolts, the screen and the frame; then lower it again.
But now, if I run into a rainy day like I did last year in MT, I can have some air circulating through the trailer without raindrops falling on my head. Maybe now, it will never rain where and when I camp.