Coastal routes get you the best scenery but your equipment seems more geared (pun intended) for trails and logging roads where scenery is scarcer.
Off the ferry is the trailway with exceptional coastal views to Stephenville. A side order of Port aux Port gives you coastal vistas and a Lloyds River/Red Indian Lake run puts you into the center of the island but avoids the slab. Backtrack to Howley on the Trailway across the Gaff Topsails and up the Northern Peninsulsa via Richard Squires Park to Cormack. Gros Morne awaits you there.
All good dirt for your pleasure.
Just offerings mind you.
If I still had every dollar I spent on motorbikes I would be a richer man but a poorer person.