NAWILIWILI, Kaua'i — Big-wave surfers Laird Hamilton and Dave Kalama completed their 430-mile trek through the state yesterday with a 26-mile bicycle ride from Nawiliwili to Kilauea Lighthouse on Kaua'i.

Their weeklong land and water journey over and between the islands was undertaken to promote a documentary film on autism made by their friend, cinematographer Don King. "Beautiful Son" is about King's autistic 6-year-old son Beau.

Hamilton and Kalama agreed the hardest part of the trek was standup surfing the 78 miles between O'ahu and Kaua'i using long paddles. It took about 19 hours.

"It's the hardest thing I've ever done, and I won't forget this anytime soon. It was a serious gut check. I'm so glad to be on land right now," Kalama said Tuesday after the overnight crossing.

Hamilton and Kalama began traversing the state Oct. 4 at South Point on the Big Island.

King, who works on the ABC series "Lost," has said he hopes the effort will help raise $40,000 to distribute the documentary to a wider audience.