Hi Billthetug,
I tend to use LED's as they draw very little current.
These can obtained from Ebay at a reasonable price so you can wire loads into the boat. I would use the 3mm ones and wire them to their resistors before fitting them in. When you come to the mast then score a line down the back to contain the wires and fit the Leds to the ends. Pull the wires and leds in tight to the mast BEFORE you think of filling in the channel with filler. If you leave the wires hanging out, intending to solder the leds on later then you are in serious trouble. Ask me how I know ????
Best of luck and don't forget some pictures as you go along.
Cheers
Ken