i have never done Berlin Overlook, but my wife has R.A. and is unable to do long strenuous hikes anymore so i am always looking for shorter hikes for us.
there is not a lot to be afraid of unless being on the ridge and looking 3000 feet down either side is what you mean by being afraid of heights.
even with that there is a solid trail to keep your feet on so it's not like being on a ladder or anything like that.
if you tried it i don't think you would have a problem, i have seen kids do it.
RA is not much fun. I have a relative that has that.
I started logging NH waterfall hikes and the difficulty of each hike. I started with the easier ones so you might find some good hikes with your wife
i don't know if you can get an idea of how wide from these pics but this us workin across the ridge.