Paddle away from things that scare you and from areas less than 6" deep.
Then run it again and paddle towards things that scare you (but still away from the shallows).
There are no serious rapids on State Bridge. What one is "cable car"? State bridge is something that any first time can do after one pool session.
1500 is easy for a beginner. 900-1000 is even easier.
Just go with someone who knows what they are doing and remember to lean away from the current and you'll be fine. If you wear a PFD, helmet, and don't stand up in the current, you can't possibly* get hurt.