I bought some coloured LED lights from Amazon but as I am not happy with the strobe effect, my girlfriend decided that we could string Christmas lights through some modular buildings (instead of putting the buildings away for the winter) so we grabbed one white light string and 5.5 of our buildings - just enough for one string of lights.
The method and results are as follows:
The light string enters at the top floor of the fire brigade and continues to the top floor of the pet shop
From the top floor of the pet shop to the middle floor of the brownstone apartment building
From the middle of the apartment building to the middle of the Cafe Corner, then a lot of lights get used in the middle and upper floor of the CC.
The string leaves the upper floor of the CC to the upper floor of the Green Grocer but by keeping it only in the upper floor, the GG loses lighting (Rave opportunity)
After leaving the top of the GG, the string goes through the Market Street patio door and down to the middle of the first floor so that it may enter the bottom floor of the Grand Emporium and spiral up the walls, ending at the chandelier.
I removed 1-6 pieces per building depending on where I entered and exited the respective buildings. Currently, she is experimenting with "outside Christmas lights" and you can see the first result in the later pictures.
For added colour, I can add a rave room to the Green Grocer and the Apartment building
Enjoy!