Hey, I did that trip last year.
Watch the construction bypassing Sudbury, I almost lost it when I hit an unmarked pavement cut. Yikes!!!!
Oh, and if you decide to hop the ferry, definitely don't eat at South Bay Mouth, seriously bad fish 'n chips, antique grease.
Coming back from Tobermory, hit 'the Grotto', spend the day, worth it if you're a confident swimmer.