Re: Rugged off road mini bike build thread.
Suspending the seat allows much simpler drivetrain setup and works great on something small like this. Pocketbike forks should be fine as well. Personally, with big soft tires like those, I would not bother with any springs. Just run the tires soft. It will ride great and be very gentle to the environment off road (which all parks and park rangers like)
The 212cc will be plenty of power especially if you gear it for 21mph top speed.
I doubt the multi-geared setup will be needed. Just get a good reduction and it should climb any hill you could want with the 212cc torque.
If more is better, then too much is just enough.
If you can't afford it, build it yourself.