I start Intergrad the same day. I feel you on the road test, glad you got another shot at it. I passed mine, but my shifting wasn't anywhere near as smooth as I would have liked it to be. It was just different shifting in that truck than shifting in cars, but like everyone says here, I'm sure you get used to it pretty quickly.
I originally applied for TCD. Some type of union issue was raised about them hiring outside TCD's, so they offered me preload, which I took. Three weeks later, I got the Seasonal Driver bid, and here I am. I'm sure that, like me, you're hoping it somehow turns into a FT Driver gig. Everyone here basically says the same thing, depends on the needs of your center, and how much seniority is in front of you. My PT sup on preload seems to think I won't be back after Peak, I suppose because he thinks we are so short of drivers here.. Truth is, won't know until it's over in January.
Best advice I've gotten here is: Do a good job, be prepared to go right back to preload after Peak and wait your turn, and that's the attitude I'm taking... Control what you can control, and stay the course.