Your National Park Service (NPS) has done an Environmental Assessment and Finding of No Significant Impact for ebikes generally, and so individual NPS superintendents can make park-specific policies on allowing ebikes. https://www.nps.gov/orgs/1207/nps-completes-environmental-review-for-continued-management-of-e-bikes-in-parks.htm
@bikepedantic Acadia felt like there were half a dozen different e-bike rental companies for the carriage roads, and the roads were being used by many more people than when I rode them a few years ago