I've built several 2-stroke cruisers for people, and they are a massive pain to keep tuned and running. They're messy, noisy, finicky, and everything on the bike gets vibrated loose over time, including your hands. If you can afford it, I'd go with an electric kit. The 2-strokes are very cheap, but they have to be adjusted frequently.

I bought the kits from kingsmotorbikes.com