We just went on the Diamond - 7/17-7/24 and did the Adventure Kart in Ketchikan. It is expensive, but alot of fun. The guides are very informative about the history of the area, and it is beautiful up there. They only allow 12 karts at one time (24 people) and that keeps things nice and controlled. It is very bumpy and they tell you if you have had any kind of surgery lately, you might not want to participate. There was one family with 2 kids, there were alot of "middle aged" adults, like us and one couple who looked to be in their 60's. So really age doesn't matter, I think the kids need to be atleast 40lbs though. We took a chartered bus (about 1 hours ride) to the Adventure Kart area, and then you ride a very nice Catamaran back to the dock where the ship is located. They have raingear to wear if it is muddy, it was dry when we were there. Hope this helps.
