Going west from Philadelphia
you can go through York (Pennsylvania)
on US 219 to Frostburg
which is a small college town. The halfway point is Oakland (Maryland)
Oakland is the county seat of Garrett Co. - in the panhandle - the westernmost part of Maryland. From here you take US 50 to Parkersburg
then go on over to Manchester
and follow the river a little way before you break off and go to Williamstown (Kentucky)
This will be about 7+ hours drive a day.
If you took the interstates - either I76 and I70 (Harrisburg
, Wheeling (West Virginia)
) or I95, I68, I79 and I64 (Baltimore
) the drive will be 4 hours shorter.