You really should ask the leader in the troop that your son would be joining, what they will be doing. Also, ask other parents, that have had kids in the troop. If it's the same leader ask questions about the leader to the other parents. Maybe you could ask the leader for reference.
From my experience, it's not worth it. It was kind of like a recess. Both times there were den mothers, because they didn't have any fathers volunteering. When we moved, the den mother was aweful, she gave the kids bad information, she didn't work on things in the book with them. They never went anywhere but the school gym. He had to sell expensive popcorn and pizza, that no one wanted to buy, so he couldn't go to camp, unless we spent a fortune. The kids were not watched half of the time, and they used to fight and get into all sorts of trouble. It was a real disappointment. Of course, if you want, you can stay and observe a few times, but chances are, they will behave differently while your there. I used to stay most of the time, I was too worried because they weren't being watched, and there was only one person watching all those boys anyway.