Wailuku Flights

Wailuku is located on the hillside above Kahului. When you arrive at the airport, you will be in Kahului, near the northern side of the 'saddle' between two mountains (West Maui Mountains and Haleakala). If you head 'west' from the airport into Kahului town, then through it, you will end up traveling on Kaahumanu Avenue. If you stay on this road, you will eventually go uphill and under an overpass. This is the 'entrance' to Wailuku town. Don't blink, because Wailuku is not that big a place. Once you get to the top of the hill and turn left, you're on your way out of town.
You should have a car on Maui simply because the places of interest are far enough apart that walking is out of the question. Wailuku town is on a hillside, and the points of interst, like the Hawaiian Tropical Plantation and Iao Needle, and the restaurants, are all on the fringes of the town and far apart.