So i'm looking into buying a vehicle that is sold with a bill of sale only.
It's on the other side of the US, so I will have no chance to meet with the
seller. Does anyone know the process (in summary) of how I go about getting
this vehicle titled in my state (PA) later on?

The reason I ask is....
my brother purchased a vehicle project a year ago out of state with a bill
of sale only. Now he went to go get it titled. Having waited a year, they
said they needed a letter or something from the seller, the seller can no
longer be found, and they have told him flat out "We can't title this
vehicle". While i'm sure there are loop holes and I'm sure he will get it
titled in the end, I do not wish to go down this same path.
Thanks

-Craig