A.V.
Visit the schools. One of my personal peeves is that sometimes schools (like SD's elementary school) get labeled with low scores, but when you visit you realize they have a lot of diversity, dedicated teachers, and just a great vibe. Don't just go by the numbers. Go by the people.
Montgomery County is pretty big. If you go much past Rockville, you'll be off the Metro, if that's a consideration for you. Are you looking for a neighborhood or a city center kind of vibe? Germantown is adding new things all the time and Kentlands in Gaithersburg seems to have a lot to offer. Maybe drive around to see what you like and then look up more info on those areas. Kensington, for example, is close to the mall, and has a lot of established neighborhoods.
You might also take a trip to a local park. Kind of check out the park, the neighborhood and talk to some of the parents who bring their kids there.
"Silver Spring" is unincorporated, so consider actual neighborhoods like Wheaton, Four Corners, Kemp Mill, etc. Look at a Google map and you'll see some of those designations. Silver Spring also has a lot of access points to Metro, all along the Red Line. So does Bethesda, but it's pricier. If commuter access is a priority, why not look at a map of the system and go from there?
I would personally choose Montgomery County over PG County and don't know enough about Northern VA to comment. Cost of living is lower there, though.
Good luck!
