50 miles, not 100 miles.
25 miles each way is not that big of a deal. In college I spent six months commuting 40 minutes each way (traffic gods willing it wouldn't be longer) from 31st street to Springhouse, PA.
Valley Forge is definitely at the limits of what I'd put up with though, unless there's good train service.
@antifuchs
Ah, that explains it. I wonder which one they live in.
Actually it's probably the York one because “Valley Forge" by Philadelphia apparently isn't really a town in its own right.