The bottom covering is called COROPLAST (corrugated plastic) and is a part of the "arctic package"... The panels that are screwed to the COROPLAST are installed at the factory to "mark the location" of the slide motors that may require access for repairs or maintenance. Usually the underlying COROPLAST is not cut, so if you remove that "patch" you'll see a "blank canvas" under them.
If, in the future, you need to access the slide motor, you'll need to remove the "patch" and use a razor knife to cut a "slightly smaller access hole" in the COROPLAST. When cutting that hole, allow at least 3" on all sides of where the patch overlays the COROPLAST and cut the hole on three sides, forming a flap on the FORWARD edge of the hole. That way, you can "fold the hole closed" and tape it in place, reinstall the patch with the 4 screws and have a "double layer, usually leak-proof access port.
As for the "arctic package" understand that it's not much more than the COROPLAST, a sheet of bubble wrap and a 2" heat duct (from the furnace) into the underbelly. You still have R-7 walls, R-15 floors, R-20 ceilings and all those leaking R-1 windows, so don't believe for an instant that the "arctic package" will provide any "cold weather camping capacity"... it'll only make things less likely to be damaged from freezing down to about 25F or so. You'll still find that you will need thermals and sweats on cold nights and forget sitting comfortably in the recliner in front of that big picture window when the wind's howling outside..... Ain't gonna happen......
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