Removing underbelly colorplast at rear of Bighorn

Hi. Need to remove the underbelly at the rear of the camper, has anyone done this before?
I don't want to remove all of it if I don't have too, hoping just a few screws and drop it. The underbelly bends up and over so any help will be appreciated
Arrow shows how far it goes into the rear cap area.

The coroplast is pretty flexible, at normal temps. I have had mine partially down before. Like you said pull the appropriate screws, which tend to break off unfortunately....and drop it down

Some aren't even screws. Ours was held on with nails - they shoot them right into the I-beams, and they aren't removable. I had to drop the front of ours when I was redoing some wiring, and just cut right around each factory screw head with a utility knife, then re-attached it with some new #10x3/4" self-tapping screws. They install very easily, so don't stress about trying to reuse the factory hardware. I used foil tape to cover the holes. YMMV.

If the coroplast fastening screws have a 1/4" hex head on them with washer, they are removable provided they haven't rusted to the frame of which they go through. You can use a 1/4" socket and gently turn them like any screw, they have a spiral thread on them, and some will break. I remove all of mine when I did an electrical upgrade, and replaced them all with 5/16" self tappers.

I've taken the underbelly off in the front, just curious about the rear where it bends up and over. Fortunately we have screws and I have replaced a few.

Tell you what I did on our old Everest I placed two low trestle either side coach with a beam across to support that under belly moving it forwards and back roll it up, never seems to be long enough when one replaces it. Your cross beam looks stronger than on mine.