Nantucket is a beautiful island and june is a great time to go with warm weather for visiting the lighthouses.You can rent bikes and mopeds in town .Just as you get off the ferry.You can find a shop on the opposite side of the street from the whaling musuem.It can be expensive. They have mopeds for two persons.They supply maps as well and Sankathy is a neat bike ride as I have done it several times both bicycling and mopeds.Great Point ,which I havent seen since 1976 was a walk. I was told it was destroyed and rebuilt and can be visted either by tours or rental of vehicle .Which is suppose to be very expensive.Brandt point is seen on the way in to port and is easy to vist by bike.The ferry times are tight. I suggest watching your time and keep your expectations reasonable or you will be dissappointed.Its a great place and the day goes by quick.Cobblestone streets in town,a windmill which is just out of town ,and can be seen on the way to Sankathy light.Some beautiful old homes as well.Have a great trip.