I would suggest fishing upstream of the Whistle bridge using a float and microjig. The ones that my daughter has the most luck in getting strikes are the pastel pink, yellow, and white, bright pink, yellow, and white, white with a red spot, or plain white globalls. Also the green body with yellow eye spot John deere jigs work really well under a float. From the bridge, the baits will spend a lot of time in front of fish. You will get some aggressive strikes, but most will be subtle with maybe just a stop in the drift of the float. So make sure that they are able to see the baits as they drift towards them and have them try to anticipate the strike. The fish will often circle the bait before they hit it. Once the fish flares it's gills, have them try to set the hook. The globalls can be a challenge in getting a good hook set, but the fish sometimes cannot keep off of them. The problem with the bridge is that you will need a net to land these fish and preferably one with a long handle to reach the fish.
Also I prefer to fish 2 lb test and think that we get more action than with 4 lb line. The 4 lb will keep the fish from breaking off. so it can be a trade off.
I hope this helps. Good Luck.