Old frig opening... Maxxair vertical installation?

[Bicyclejames]

I removed the frig from my scamp and was going to attempt a fiberglass repair of this opening (but with the belly belt right in the middle, I was leaning toward some kind of external cargo bin or something) when I saw someone here had put a Maxxair vertically mounted to ventilate their bathroom. Does anyone have any notion as to whether this would work as a solution for this rather large hole in the side of my rig?? Would the opening have to match up exactly? I don't currently have a vent other than the escape hatch opening and windows but have been wanting to put in a fan like this for quite some time. Just never thought of the vertical option or turning a blight like this frig opening into something useful.

A second quick question--are the wood ribs/mounts for cabinets something that can just be cut off if I'm changing the cabinet locations? At first I thought they were actually part of the shell and fiberglass through and through, but now I think they are just wood "fiberglassed" to the shell. Am I right about this? Do I just follow the seam with a dremel or something? I have nightmares of cutting through my shell...

Thanks in advance for any help/comments.