Here in the upper Midwest we’ve had experience with this.
Expect the eco-fascists to make wild claims.
They will lie and attempt to ignore and ultimately nullify the park’s original charter.
Their ultimate goal will be to ban people from the park.
I recommend you contact the people here:
They’ve already fought a similar battle, can give you advice and strategies to fight the eco-fascists and may save you time and money in researching the various legal paths you’ll need to take.
Go here for a synopsis of IRBA:
http://www.isleroyale.org/about/history.html