These days I feel that I can get a nice lighting effect without all of the extra parts and effort. Another problem that can ruin a lighted model is if the buried components fail. Now you suddenly have an unlighted model that will be very difficult if not impossible to restore to illumined glory.
There are tiny hard core Fiber Optics and LED that will probably last for years sure, but I am not going that way.
I found some easy to use Tea Light options for my large models that will look awesome when I am done. With these easily replaceable lights you only have to set up a very accessible magnet male to female plug system that you can simply make with plastic telescoping tube.
Now if a lighted model fails me for what ever reason, I can just switch out a Tea Light that cost all of $2 (at most) and in about a minute I have full lighting again...1-2-3-simple and affordable. If you want to go this route, I recommend that you do spend the tiny bit of extra cash and get Submersible Tea Lights because they are water proof, which means that they are split paint and running glue proof too. Ha!
There are all sorts of LED Tea Lights available, try a quick search at Amazon, and find a set you like. Have fun with your projects and remember the K.I.S.S. approach my friends.