Scenic Caves Nature Adventures has expanded their operations since I started going there as a kid. Just last year they built a suspension bridge that lets visitors walk above the treetops. There isn't much on the other side yet, but I'm sure that's in the works.
They also have a few other sights. A nice park area for kids to play in. A trout pond with fish and swans. A Gemstone Mining stream where kids can sift through sand to pan for precious (to them) stones. A mini-put golf course and the gift shop round out the day.