This is the headquarters in Bayfield.
There are plenty of other activities, especially if you are willing to pay for them. There is an Apostle Island cruise available. We chose not to do that one due to the cost and duration (3 hours!) of the cruise. You can also fish, tour some lighthouses, and there is plenty of hiking!
The park may be accessed for free, but there are fees for many specific uses.
Apostle Islands National Lakeshore
415 Washington Avenue ~ Bayfield, WI ~ 715-779-3397