West Maui
Drive it clockwise, Kapalua towards Wailuku, so you stay on the mountain side rather than the cliff edge. Past Nakalele the road narrows to one lane with blind bends, no guardrails and steep drops: give way to local drivers, be ready to reverse to a pull-out, and skip it if the traveller is a nervous driver, in heavy rain or in a large vehicle. At Nakalele stay well back — rogue waves over the lava shelf have swept people in and killed several. Kahakuloa is a residential village; stop at the roadside banana-bread stands (cash only) but drive slowly.
Free, no booking. From Kapalua follow Route 30 past Honolua Bay and the Nakalele Blowhole (between mile markers 38 and 39, dirt lot, no water or restrooms), where the road becomes Kahekili Hwy (Route 340) through Kahakuloa village to Waiheʻe and Wailuku — about 20 miles. Many rental contracts prohibit Route 340 between Honokōhau Bay and Waiheʻe; driving it can void cover for breakdowns and accidents, so check the agreement. There is no cell service; download maps and start with a full tank.