It's hunting season. Wear orange.
North-South Lake has really nice views, of course, but don't they close the gates after Columbus Day? If they're not open, you'll have to walk in from the Schutt Road parking. There are still nice hikes that start from there, but it won't be a quick 3-mile jaunt unless you do just the Mountain House site.
One thing I did with my daughter when she was a kid was the in-and-out to the base of Kaaterskill Falls and then the in-and-out to the top from Laurel House Road. She loved that one. If you son and daughter-in-law haven't been there, it's surely worth a visit.
Or how about the Overlook Mountain or Mount Tremper fire tower? Overlook also has the ruined hotel to explore. I don't have time to look up the mileage, it might be a little longer than what you asked for, but it's all on a maintained gravel road. The television people still drive up there to maintain the tower. The fire tower cabs will be locked, but there are still great views from the top landings of the stairways. Red Hill is an even easier hike in, but the view isn't quite as spectacular as the others. (Balsam Lake Mountain has spectacular views, but the easy way in is a good bit more mileage than you're asking for, and the short-mileage route is pretty scrambly.)
Acra Point from the end of Big Hollow Road might also be a possibility. I don't remember how far the first viewpoint is from the Batavia Kill trail junction.
If you're willing to spend a little $$$$ and make a day of it, ride the chairlift up Hunter to Colonel's Chair and hike from there to the summit. Whenever I've been up there in good weather, that's how most of the people I met got there. (They've expressed considerable surprise when I told them, "no, I climbed the mountain from the other side.")
None of these possibilities involves any rock scrambling. I'm presuming that if you're looking for about 3 miles, you want to avoid the places wheree you can touch the trail in front of you without bending over.
Watch the weather. Mid-November is getting dodgy at high elevations. The Escarpment should still be safe, unless we have a really freakish year, but there may be ice on the peaks even that early.