I hope you and your wife enjoys your kayak trip. I fish a river here but for mostly different types of fish. I find in a lot of cases if the current is strong the fish will travel closer to the shoreline. I am thinking it is because they can get out of the current behind little points that may stick out from shore. Also any rocks that maybe out in the river has little hiding places for fish to hide in. As Chuck has stated the line and drag are the 2 biggest things you would want to worry about when starting out. Current requires you to play out the bigger fish. They are surely fun to catch in moving water and you need to hang on your rod pretty tightly once you start getting hits. My favorite hook size is a #4 eagle claw. You would also want to add swivels to your line to keep it from twisting up on you.

I also agree with letting the little fellow catch some sunfish when he can. As stated it will give him enjoyment when they are on the bite. I like taking my grandson with me to catch white perch and I enjoy every bit of watching him reel in a fish. Good Luck to you and your family. Enjoy your fishing outages with the young fella..