My wife and I are coming to Hawaii in January 2015. We are planning to spend some time in Waikiki and one other island for 2-3 days. We are tossing up between the Big Island and Maui. We plan to do a zip line adventure and from what I can gather there are good operators on both islands. The drawcard for the Big Island is the Volcanoes National Park. Given it seems unlikely we will see lava flow how does the Haleakala Crater stack up against the Volcanoes National Park ? This is essentially the factor that will decide which other island we visit. Any advice would be appreciated including any other attractions on either island that would help sway the decision.