When my son started as a Tiger, we had almost all the meetings at the Den Leader's house. She worked Monday through Friday and couldn't really have a meeting except on the weekend when the school was closed. The parents were there, of course, and they did usually participate when we had a craft or kite flying or something similar going on.
When he was a Wolf, we began to rotate the Den meeting to each parent's house. Since the parents drove the boy to the meeting, they stayed, and again, they participated when we were teaching something to the boys (i.e., compass skills, knots, etc).