We visited Volcano National Park, in Hawaii, and rented e-bikes so could see as much of the park in the short amount of time that we had. We rode almost all the way around the largest and currently active caldera. The ride was over 21 miles long, starting and ending from the Bike Volcano rental shop. This was a great way to see the park and get in a bike ride.

Bike Volcano bike rentals - https://bikevolcano.com/

Volcano National park - https://www.nps.gov/havo/index.htm