I hope this reply isn't too late. Just came back from a similar trip myself!

A few thoughts to add to Seat13F_AC_CRJ's great suggestions:

- In St. Andrew's, go to Minister's Island as a great intro to Fundy's shores. You can drive over in low shore and take a boat over in high shore. You can get the times from NB Tourism or Minister's Island) directly as they change daily with the tide.

- We stayed at the Hampton Inn at Moncton for a night. One of the nicest Hampton's I've been to (it's relatively new and didn't show up on many hotel searches we did).

- Right after Fundy National Park (great place for a picnic, btw) you can take a detour just past Alma to visit Cape Enrage lighthouse on your way to Hopewell Rocks.

- Highly recommend Hopewell Rocks! If you didn't see both high and low tide at St. Andrew's try to catch it here ... it's really worth seeing both somewhere along Fundy.