Kev,
I have used the Bowser caboose lighting kit, mainly for the pickups on the trucks. I used a very dim amber LED in the interior since I have never seen a caboose that was very brightly lighted, it would ruin night vision, just a small shaded lamp over the captain’s desk. Mainly I wanted lighted markers and the setup works fine for me.
Take a look at this old thread for some more ideas.
http://cs.trains.com/mrr/f/744/t/83476.aspx?sort=DESC&pi314=1
The Bowser part number is 74060. I see that Ring engineering has pick-up trucks as well but seem to be a bit more costly than the Bowser.
Have fun…