beautiful to spend a day at the islands, unfortunatly the whole island operates on a seasonal basis, and summer would be the best time to go, as everything is open in the summer time. i walked for over 3km before i found a bathroom that was unlocked. not very much vehicle traffic, as only service vehicles are allowed to drive on the island. lots of bike riders to be careful of. and rentals of bikes are only during the summer months. but you can always bring youre own bike on the ferry.
bring a camera and some comfortable shoes, you will be doing lots of walking.