fasttrax is a good series for the "new" racer. I say that because although there are some really talented riders there, the atmosphere is usually a bit more relaxed, and the grids are less full. You can go race and get in some experience, without 3 waves of riders jockeying for position.
Nelsons isnt the best track, but it isnt bad either. On a 600 you can take the kink on the back straight a little bit off of full throttle (thats damn fast to go through a turn).
I recommend checking it out at least once. Why not??? As a matter of fact, they offer mini-enduros which would be perfect for you. I think they are three 30 minute races, where you run against the clock. Great for seat time, and your learning curve.
Like boxing said check out their website for more on schedules. www.fastone.com