I had the good fortune to find a house overlooking the Catawba River just below the Mountain Island Lake Dam. Since then I have taken numerous kayak trips from there.
The closest official put-in is at the Route 27 bridge in Mount Holly. Head north from there and you will discover one of the most untouched stretches of the river. During the week you will rarely see another person. You will however see plenty of wildlife including hawks, osprey, snakes and even wild turkey on some occasions. I like to occasionally take my fly rod out and fish while floating. The blue gill are always biting and you might hook a big bass once in a while. Mostly it's a relaxing paddle up stream and back. You might get a good work out when they are releasing water from the Dam, but there is nothing resembling whitewater.
I have a good friend who lives up river and we try to make paddles once a week but I'm open to showing others around. Send me an email at firstname.lastname@example.org if interested.
The launch is barebones self-service.
Drop a buck a person (not per boat) in the honor box.
From I-85 south of Charlotte take the inner loop of 485 to hwy 27 south to Mount Holly. Take your first right after crossing the Catawba River and work your way down to the launch.
Walmart carries maps for Lake Wiley and Lake Norman.