Like the cuda said, likely small to flat, but you never know in Aug. Long sands is perfect for longboarding when small, but crap if a real swell shows up - the kind of wave that crumbles a mile outside and mushburgers in. But then there are some good options not far. Come trip time, if an actual swell is imminent, pm me, and I can point you to some quality nooks and crannies, of which there are many.
I'd carry a board. I was just up there and two good swells hit in a weeks time. Granted it was winter but August isn't the worst time in summer. We drove all around the coastline and Higgins Beach looked like it had the most potential (of the places we saw) Why not keep going and hit up Nova Scotia?
Not much difference, really. Both are prone to flatness in summer, without a swell-maker within the swell window. But NS has some sweet points, and is relatively uncrowded, even in the summer.
Yeah that's what I'm saying. I love Nova Scotia. It would seem like more of a surf trip and if all else fails explore the Cabot Trail. I've seen some good waves around that area and I'm pretty sure your wife would love it too.