Renting a Car - Where to park/ any costs involved?

We are typically carribbean cruisers who are used to getting a taxi from the cruise port & going off to the beaches & shopping. After reading all the posts we agree that we may need to rent a car especially for Maui & Kauai & maybe Hilo. It looks like most of the rental companies are at the airport, so Im assuming they have a shuttle that picks you up at the pier & bring you to the airport to get your car. With that said, POA has 2 overnights both in Maui & Kauai so if I was to rent a car overnight where do I park it? Are there any costs involved for parking? Once I park the car, how do I get back to the pier is it within walking distance? Lastly, once you bring the car back to the rental agency at the airport, does the car rental place bring you back to the pier for free or is this another expense by way of taxi?

Just a quick look down the board:

https://boards.cruisecritic.com/showthread.php?t=2437729

https://boards.cruisecritic.com/showthread.php?t=2620794

https://boards.cruisecritic.com/showthread.php?t=2625872

https://boards.cruisecritic.com/showthread.php?t=2511500

and many others.

You don’t have to rent a car at all in some places depending on what you want to do. In Maui if you want to drive the road to Hana rent a car. If you want to go to the beach for the day- take an Uber.

All rental companies are not the same. You would need to contact them directly to find out if they have a shuttle to and from the pier. You would also need to ask about overnight parking. Also find out what time the office closes and whether there is a way to return the car if the office is closed. The second day on Kauii is short and you will need to be back on board by 1 pm. We ended up returning the car we planned to keep overnight at the end of the first day to avoid the parking hassle. I can tell you that Thrifty on Maui and Dollar on Kauii have shuttles to and from the pier.