It is highly unlikely that you would be able to receive Baltimore County or Baltimore City from Northern Lancaster County, Pa. Both of these jurisdictions are on 800MHz, due the distance and propagation of 800 MHz signal I don’t think you would have enough for the trunk tracking scanner to decode the data channel.
I am unsure about other jurisdictions in the State of Maryland, but for most of them it would be the same problem. Maybe another member of this board has visited your area and knows if this is possible.
Larry