I ordered a soldering kit and the LED's, but that looked like way too much work since I was only wanting to use it for an evening. So, I stuck an LED strip in there and drilled holes through the back where I attached it to a couple of 9V batteries. Worked pretty well, really. I used Prusament Azure Blue and it was decently transparent.
I did have to use my side-cuts to break off some of the ribs on the bottom tray so my pieces would still fit right.