Hawaii - Adventures in Hilo with kids - Ziplining, flumin da ditch?

We are taking our 4 kids (17,13,9,7) + grandma to Hawaii in January, staying in Oahu for a week (3 nights at Royal Hawaiian in Waikiki & 4 nights at Turtle Bay on North Shore) and then 3 days in Hilo on the Big Island.

We'd like to take the older ones ziplining, anyone use Tom's Barefoot Tours for ziplining on hawaii? They have ziplines on both sides of the island and since we are staying in Hilo area, thought we'd use them.

I've also read that flumin' da ditch is fun for families. Anyone done that and is it worth the time and money?

Any recommendations for other activities? Here's what we are planning on doing so far:

Waikiki, International Markets, Pearl Harbor stuff, Polynesian Cultural Center with Luau, North Shore beaches (Waimea Beach, Sunset Beach).

Thanks for any suggestions.

flumin closed down some time ago.
zipline had a recent fatal accident during maintenance...not sure if open....

here is a link for adventure bookings Hilo side:
http://www.kapohokine.com/

http://www.flyertalk.com/forum/hawaii/1082607-consolidated-must-do-list-big-island.html?highlight=Must

flumin closed down some time ago.
zipline had a recent fatal accident during maintenance...not sure if open....

here is a link for adventure bookings Hilo side:
http://www.kapohokine.com/

Flumin is back. http://adventureinhawaii.com/bigisland_kohala_ditch_adventures.htm

I use Tom Barefoot's site for info but book direct through the companies. Usually they will match his prices.

If you've got the funds and the volcano is pumping, a helicopter tour of the volcano area is a memorable experience and all of the tour companies are excellent. There are also airplane tours of the volcano if you're leery of flying on a helicopter.