>>1034169this
>>1034440 if you can stand the tourists
also on the Brunswick line Brunswick and Martinsburg are OK but again, an overnighter because no day roundtrips from DC
On the Penn line Edgewood is a comfy little station but the best is Perryville at the north end...there's a nice park right by the Susquehanna bridge.
On the Camden line St Denis used to be a nice spot but I don't know now.