Buffalo515

I've thought about using fiberglass or foam to close the gap up, but wanted to post to the forum to see if anybody has any creative ideas. I got the bed cap for 20$, so I am really trying to make it work. Looking mostly for ideas that prioritize aesthetics lol. I have most tools and access to almost any (my skills with each greatly vary though lol). Not sure why it keeps rotating, but the second picture is what the truck looks like present day.