Sounds like you nailed it on the legal definitions of the vehicle.
Geared sprockets are great because you CAN change your gear ratio's easily later.
On my Electric Kawasaki KZ440, I started with a 72 tooth gear on the back and a 12 tooth on the front. When the 12-tooth broke (terrible home-weld!) I replaced it with a 14.
That setup has enough power to spin the back tire, while still being able to hit 45 mph top speed. I haven't yet experimented with going to a bigger yet front sprocket as it's 25 mph speed limit in most the area I use the motorcycle.
It might be fun just to experiment with sprocket changes sometime though!
