REAR ACCESS UNDER SHELF: There is a lot of room under the rear shelf of our LG5W. We do not have water/plumbing, gas, or a stove. The access from the end of the bed is inconvenient at best. I wanted to provide easier access from the top.
6 INCH PORTAL INSTALL: You have to work from underneath first. There is quite a lot of wiring and some support braces that you want to avoid. These limited me from putting a great big rectangular port hole. Turned out that a 6 inch opening is plenty generous.
Do some basic measurements and start with drilling a ~1/2 inch hole toward the center of an open space. Use that point as a reference to avoid the wiring and braces then break out the jig saw. I took a cautious approach and cut a ~2 inch hole first so I could ensure that I was missing the vitals. Then follow the instructions for the portal you bought and cut the hole to size.
Installation is really easy just needing a few screws (since I was not concerned about water tightness or structure, I only used 2 screws).
I cannot tell you how USEFUL this space is for soft items. We keep our towels, paper products, and many, many other lighter, softer, or padded items.
This modification was very helpful when our tail lights went out (another post).
THIS IS THE BEST ~$20 AND HOUR I HAVE SPENT ON OUR LG.