Easy
Koali Pond: A short 5 minute walk away. From the cottage turn left up the hill, curve right and proceed to the bridge. The pond is a little wading pool with a never ending waterfall feeding it. Favored by locals and visitors alike. Take lots of mosquito repellant.
Wailua Valley: Twenty minutes away. Keep going past Koali Pond and carry a stout stick to discourage curious dogs.
Waianapanapa State Park (MM 32 on north highway): Park at the park. Walk down to the caves and jump in to the ice cold water (well maybe not icy, but 50 to 65 degrees F).
Walk out around the point and observe the blow holes and water spouts
Haleakala National Park at Kipahulu: MM 42 on south highway. About 8 miles south of Hana. Walk down to the lower ponds; swim. Walk along the shore to the south. Walk back up along Ohe'o Gulch. It costs $10 for a week's worth of parking at the park.
Moderate
Waianapanapa State Park (MM 32 on north highway) to Waikoloa Point on the north side of Hana Bay. Two Miles along the spectacular shore. Park your car at the State Park. The State Park is about 2 miles north of Hana Town. Take water.
Waianapanapa State Park to the airport. See above
Kaihlulu (Red Sand Beach) Start at the ball park in Hana Town. Park, Walk away from the mountain toward the old school. Turn right, then turn left just before the Hotel Hana Maui Cottages.
Continue thru cemetary to cliff above shore. Follow along the bluff to you see the beach below. Tricky...step carefully.
A Little More Challanging
Haleakala National Park. Waimoku Falls, about 1.7 miles, up from the parking lot. Through the clunking bamboo forest where you can enjoy the aroma of ginger in season (July-December).People do it in slippers, but the footing is very uneven cluttered with exposed roots
Challenging
Kaupo Gap into the Haleakala Crater. Up from MM 35 on south highway. It is a one day trek. The gap is part of Haleakala National park. First go the Kaupo Store (But it probably won't be open early) then go back a quarter mile to a paved road that goes up. It butts into a cross road. Go left and follow road to National Park parking. Park. Folow signs. Three or four hours later, you be at 6,000 feet elevation in Paliku. If you sign up with the park rangers, you can camp at the cabin. There is water there. You need reservations to get into the cabin.