My wife and I are heading to Maui in late March. My Mother-In-Law has a time share, so free accommodations! WooHoo

We are planning on doing the "Road to Hana" road trip, a whale watching trip and taking a horse ride into the Volcano on Maui. If we can afford it maybe a trip to the Big Island and check out the Volcano there, my wife is a Geologist, and both of us want to see some Hot Molten Lava!

Any other cool sights or locales on Maui that maybe only a local might know?