Not happy how big the hole is behind that light. Think I might try to find a led strip like on my awning and go across the box. Think I'll buy a tote for it and use this to store other stuff like the messy patio mat.
I have a box like yours across the front.
As far as the hole in the trailer, you could build up some silicon to seal it. I would use a small piece of Gorilla Tape, cut just slightly larger than the hole and cover the hole, then cover with some silicone caulk again larger than the tape. The tape will keep the silicon from entering the hole and the silicon will cover the tape. If you are going to use the wires, then get a grommet and seal the hole with silicon.
There are a ton of LED lights at banggood dot com... Chinese warehouse that takes 2 to 3 weeks to get stuff from, but it always gets in my mailbox and the prices are cheap, cheap. Don't be put off by the Chinese characters on the packages. I bought a bunch of LED battery operated lights that turn on with motion. I put these in all of the cabinets and storage areas so when I open a cabinet the light turns on. I just got 3 lengths RGB LED lights just like the awning kind, $10 each delivered with Remote Control and power box (needs fed 12V) 5 meters long. Waterproof to IP66 spec. Pay with PayPal so transactions are secure. You can purchase tracking and insurance, but I have not paid for either since last fall and have never lost a package yet... course I'm not spending a ton of money either on any one order.
5M 5050 RGB Waterproof 300 LED Strip Light 12V DC - US$9.99
As far as the outdoor rug, I have attached with drill screws some D-ring loops to the two opposite sides of the tongue box. I lay the folded rug, actually we have two, on top of the box and use several bungee cords to strap them down on top of the outside of the box. No mess inside the box, and the rugs stay put for travel if you are careful strapping it down. I keep my power drill for the stabilizers, the wheel chocks and some 2x6 lumber for pads, plus a couple of small hand tools and a flashlight in the box. The box is the last to be closed before we go, and then the rugs get strapped on top. It is also the first to be opened when we stop to camp and everything is right there that I need to set the stabilizers and chock the wheels.
I have seen channel for these lights for sale on the net... just will have to find it again...