I was also at the season pass preview day. The hours were 12-5. ROS was down for the majority of the day.
At 4:40, the sun came out, and after some more ROS tests, the handful of us that were there were let in to board at literally 4:59. They were nice enough to run the ride until about 5:15 and cycled maybe 6 rides, which I got 3 of with having to walk around.
It was pretty gloomy and windy and sprinkled on and off, with some heavier rain for about 5 minutes at one point. I got on each of the coasters except Motocoaster, which looked like it had the flywheel running and had ops in the station, but I never saw it run.
I rode Mind Eraser totally alone, as no one was really in that area of the park.
The free Tim Horton's for the season pass line before opening was really nice. The park looked decent. Viper has a nice newly painted sign.
All in all, I was just glad they worked to get Ride of Steel open even when the park was only open for another 10 minutes. It ran super slow, but it'll get there when it gets warmer out.