I would rather plan my own. We are the type of family that avoids campgrounds and love to scout out a camping area and really rough it out there. SInce we rough it that is probably the reason we only do it once a year. 

It depends on what the activity is. We've sometimes participated in the activities and have really enjoyed it when we do. Part of the fun of camping is meeting others with similar interests.

When my kids were younger I enjoyed having some planned activities available just incase we ran out of stuff to do on our own. They always enjoyed craft projects or games, while I'd prefer guided hikes, etc to learn about the area from someone that really knows what they are talking about. 

Also, my kids are very social so even now that they are older, they enjoy mingling with other campers- especially if they are the same age, opposite gender and cute. *grin* Just trying to step into the mind of a teenager, that's all. :) 

I actually love having things planned for me. If I don't then I usually just sit around and relax...which is one of my favorite things to do, of course!