Mostly not too bad. It's pretty clever how they hide a bunch of the wiring under the tea house. You have to kind of braid a bunch of it and shove it under a little lego hide along with the connection board. That was tricky. I made my daughter do the braiding.

This is the second set I've done a light kit for (the first was the Daily Bugle set. Talk about jumping into the deep end...) so I kind of knew how the wiring worked with the bricks at this point. The instructions were pretty good and the wiring was pretty good as well. It didn't come with a power source and it wants a usb power source instead of a battery pack or something, but I had some old usb power blocks running around, so that was fine.