The obvious answer is to look at the places off of I-83 just over the border from Shrewsbury to York. You might also consider places just over the border from Carroll County in the area around Hanover or the area just over the border from Harford County around the less congested region of Fawn Grove. As I-95 is expanded, the commute may be come more bearable such that going over the Susquehanna River and then through Cecil County to the parts of Pennsylvania around Oxford may be an option. Keep in mind, that commuter train service already goes from Baltimore, through Cecil County, and onto Philadelphia and points north. Local mass commuter service going north of Baltimore up the I-83 corridor stops at Sparks.
If you have a home to sell in the Greater Baltimore region, I can help you with that. If you are looking to buy in south central Pennsylvania, I can refer you to one of the top agents in that region.