I did a track day at Dunnville a couple of years ago with the Miata club and it was a blast. The track is short and technical which keeps the speeds down.
We had some instructors who did a chalkboard session, then drove us in groups around the track to show us the line. We then broke off with an individual instructor who drove you in your own car to show you the line. My instructor was Bill Brack (
http://www.motorsportscentral.com/brack-interview.asp) who just looked like any old guy but is an amazing driver. He put chalk on the sidewalls and we took off and he scared the hell out of me. He was very smooth, but incredibly fast. We came in and he adjusted the tire pressures and we were off again. He said he got the car neutral and loved the turbo coming out of corners.
I have never experienced anything like that before. He said he was only driving at eight tenths because he didn't want to damage my tires too much. Then I took the wheel and tried to replicate his performance with him as a passenger to no avail. At the end I did a bunch of solo laps and really got a good feel of my car as it approached the limits. It was an absolute blast!
I thought it was very safe as they grouped us by speed, allowed no passing, and had large grassy run off areas. You were black flagged and held off the track for 30 minutes for a spin or leaving the track. The second mistake would end your track day.
You can see that Brack was a very successful racer in his time. He was followed as Formula Atlantic champ by Gilles Villeneuve!
I don't know if Dunnville is still operating, but I highly recommend it as the speeds don't get too high. I could not believe how much gas I burned in a couple of hours. I put tape over my plates so I couldn't be identified in photos.