I used a 12 volt "spotlight" type light on the interior. It works, but makes too much light, gets very hot, and is a hand burner when reaching for the switch to turn it off. I replaced it with the same style light that I used for reading lights, and built a box for the wiring, which also holds the switch for the outside light. I combined this box with a magazine rack. Here is a pic. The inset shows the old light and clock which I removed.
Who needs a clock when you're on teardrop time?
Sam