Per my other post, count this as another vote for Boonsboro
If you're doing a rental, try Frederick County as well - maybe Walkersville or New Market - this will put you closer to shopping & dining and public transit, if these are important to you.
I'd say that most schools in this area are very safe, if not up to the same standards academically as the nicer areas of Frederick County (Monrovia/Urbana/Mt. Airy etc), or especially if you went further west or south (Howard County - Glenelg or River Hill high school districts really can't be beat pretty much anywhere in the country).
North Howard County will put you about 40 mins from Hagerstown if schools are the #1 priority. Boonsboro is likely your best choice overall though, especially if you hate commuting as much as I do...
Good luck!