What's the nearest big city to Dover Plains? How long does it take to get there?

The closest city to Dover Plains of any consequence is probably Poughkeepsie, and that's about 35-40 minutes away. Danbury, CT is of a similar size but is about 45-50 minutes away.

If we're talking about cities with populations of 100,000 or more, New York City is about two hours away, give or take a few minutes. Waterbury, CT (110k people) is about 1h, 15m away and Hartford, CT (125k) is about 1h, 45m away.