Best Routes from Maryland to Pittsburgh?

[DmanSlam]

Hi, I don't post much in here, but read a lot of the threads. I have a friend who is doing a ride between these two cities (see title) in support of Partner's Seeking a Cure (for Primary Sclerosing Cholangitis, or PSC for short).

Anyway, does anyone have experience with cycle-friendly roads that are safe to travel between these cities?

Any knowledge of the topography, or online resources for planning such a trip would be helpful too.

Thanks.