We visited the Hawaii Plantation Village in Waipahu (Oahu) and cannot recommend it highly enough! An outdoor museum documenting the life of various immigrant groups on Hawaiian plantations, our 2 hour tour was given by Auntie Espy who grew up on that plantation, and was a wealth of information and stories. She even brought food and fed us a homemade Philapino lunch. Be aware that Espy is the only tour guide who cooks for her group, and she only gives tours on Mondays at 10am. I am sure the other tour guides are good and informative, but I can't imagine they would beat Auntie Espy!
www.hawaiiplantationvillage.com