Hello,
I'm new here but I wonder if I could suggest that you buy a large string of christmas LEDs, most of the wiring is done for you then, and you can buy soft lights etc, they come in various numbers of LED's and I have used these with some success on slot car tracks in the past for various projects, also LED strips are very useful, albeit the quality can be interesting on some, but they do also generally have a dimming capability and are pretty good to use with minimal wiring required.
I hope that this sows some seeds of inspired thinking and doesn't upset the purist modeller who would wire these from scratch.
Anyway these are just a couple of quick suggestions.
Kind regards