Where can I take the 9 yr old boys camping? (Within 10 hours of Dayton, OH.)?

I would like to take my 9 yr old boys camping. I was thinking of Branson, Missouri but after looking at the cost of every attraction I'm rethinking the destination. We've been to Gatlinburg, TN. I would like other suggestions...with relatively cheap attractions (putt-putt, bumper cars, etc) and within 10 hours or so of our home. Thanks!!