We returned from Nova Scotia about two weeks ago, and I can hardly tell you how much we enjoyed our visit there. We are eager to return.
I agree that it might be best to stay in a couple of different places.
We spent only one night in Louisbourg, and it was enough for us. Very interesting place, and worth several hours, but we probably would not have stayed a whole day even if we had not planned to leave by mid-afternoon. I loved this place--history without the Disney aspect and sweet little "Ye Olde Sweet Shoppe" signs.
Although it looked like there was a lot to do in Sydney, we didn't plan well and only drove through after visiting the giant violin and visitor's center. Too bad--would have enjoyed a stay there.
On the west side, we stayed in Mabou. I don't think I'll ever forget the warm welcome we received at the Red Shoe Pub. We bumped into co-owner Raylene Rankin almost from the start, and she checked on us a couple of times to be sure we were having fun. Great place--though hot and muggy in early August!
One thing to be aware of when planning driving times is that road construction is a major issue. We drove from Louisbourg to Halifax on the less-than-most-major highway and were delayed 20 minutes or so at each of 4 construction sites. The crew doesn't let a few cars go one direction, and then the next few cars the other. They wait until there are about 60 cars waiting...a major inconvenience. So if you can find out where construction is happening, try to avoid it.
Have a great trip. I'll be wishing I were there again. I've joked with my friends that I would move there if it weren't for that little thing called WINTER. Doesn't work for this California girl. =)