On the weekends Flying Fish is typically a 5 minute queue. Maybe a little busier on school holidays, but it will always be shorter than the Scorpion Express at Chessington
Lumber Jump, Timber Tug and Rocky Express frequently operate with empty seats.
Banana boat typically walk on.
Quantum may have a 5 to 10 minute queue.
Depth Charge 20-25 minutes depending on the weather. I've never seen it reach the bottom of the stairs anymore.
Rumba Rapids will be walk on typically until midday, then increase to maybe 25 minutes, longer if warmer.
Dodgems likely minimum 25 minute queue.
Storm surge will be at 40 as soon as it opens.
Edit: I don't know all the height requirements on these rides, so just listed the parks more child friendly rides
Also the queue times can be checked outside of the (occasionally unstable) app here:http://thorpepark.tv