There is a world of difference between riding 70 miles one day and riding 70+ miles day after day.

I have never planned a bike tour that included a 97 mile day. Since this is a new thing for you, I'd suggest you not either. Can you get your starting/ending point closer to Acadia? There are buses in Acadia that have bike racks so you can save the riding along the roads into/out of Mount Desert Island.

Since your last bike tour failed, I'd focus on making it easier to succeed than simply dividing some arbitrary distance by your time off and assume that a) you can do that and b) you will enjoy it.

There are few worse things than having to ride long days just to keep to some schedule. Far better is to have extra time in your plan so that you have enough flexibility to change things as opportunities/problems arise.

Bike touring is challenging. It shouldn't be at the edge of your ability.