What public transport exists
Hele-On, the county bus, covers the island on limited routes with limited frequency. It is a genuine service for residents and a poor fit for visitors with luggage, resort addresses, and dinner reservations. There is no airport rail and no resort trolley network.
Rideshare reality
Rideshare exists in Kona and works reasonably in town during daytime hours. On the Kohala Coast, at gated villas, and after about 9pm, supply drops off sharply. Plenty of visitors have stood at a resort gate watching a request time out. Do not build an itinerary on it.
The approach that works
Book a private airport transfer both ways, add a chauffeur for the two or three day trips you genuinely want (Volcano, Mauna Kea summit sunset, Waipio and North Kohala), and reserve evening transfers for dinners off property. For most one-week stays this costs less than a rental plus resort parking, and nobody drives home in the dark.
When you do want a car
If you are chasing beaches daily, staying in a remote vacation rental, or moving across the island several times, rent. A hybrid also works well: no car for the first few resort days, a rental for two mid-trip days, then a transfer out.
