We're heading up there at the end of this month ---- staying at the Harborside Hotel so we'll be right where the action is. We plan on hiking Arcadia, hitting Cadillac Mtn, and either a lobster boat or whale boat ride, so those bases are covered.
It's a wonderful spot. Indeed - take a bike (not a road bike). Go into the park early in the AM as parking is crazy and usually filled by 10am. Utilize the bus system. Hike the coastline trail. I find all the carriage road bridges very interesting. We stay down in Seal Harbour as it's quiet down there and there is a little beach.
Go now, in a few years it will all be under water now that we have pulled out of the Paris Climate accord