If you want to explore the island during your stay, a rental car is your best option and all the major companies are available at the Kahului Airport.
If you need a large vehicle to transport a large group or a lot of equipment, check out www.mauivans.com.
The Kapalua Resort Shuttle provides complimentary transportation to and from the West Maui Airport. The shuttle will also take you between any two points within the resort. Simply call the shuttle service center at 808-665-9110 and a shuttle will be dispatched as soon as possible.
On Saturday and Sunday, please park in the XTERRA Event lot by D.T. Fleming Beach. Take Hanoapiilani Highway to Kapalua. Pass the entrance to Kapalua Resort (Office Road) and turn left at Lower Hanoapiilani Road. Follow the road to D.T. Fleming Beach and turn right into the parking lot just past the pre school.
Airport shuttle from Kahului Maui is available via speedishuttle.com. Please book your shuttle in advance of your arrival/departure.
There is bus service on Maui but you can't bring luggage on board. it's good for getting around locally and has a bike rack on the front. However, the bus makes frequent stops and it takes some time to get around. http://www.co.maui.hi.us/index.aspx?NID=605