Casey Jr. is one of the few rides I've never ridden (it's along there with the Monorail, Main Street Vehicles, the Canoes, and the Submarines; also have never been on Tom Sawyer's Island).
I totally recommend doing it. It's like a roller coaster when the train gets over the hill. (I think I can. I think I can.) Riding backwards gives a unique whip feeling. DLP's version is even better as a coaster.
I prefer the benches, but I'm not usually close enough to the front to get there in time! Being a taller person means there's a lot of contortion if I have to get into the cages.