You can check with Greyhound Bus Lines but I doubt they have a route through Berlin, they usually run the interstates now.
Philly to Lancaster may be another story so check each separately.
There may be an outside chance that there is a tour company from either city into those areas as a last ditch option - do the research.
I'd look at a tour company. Once you are in the area, you are in a rural setting and will need transportation to get around. It is a wonderful, peaceful area to visit! Enjoy your trip!
Thanks. I will check it out.