I personally wouldn't take a bus or car directly to Baoding, because PEK is in the NE corner and Baoding is SW, so you may deal with some nasty traffic, and the buses can be filthy.

Oh yea, and during the winter the pollution can get crazy bad, with smog potentially decreasing visibility on the road and increasing traffic accidents.

If you don't have a lot of luggage, fastest way is to buy a train ticket upon landing at PEK (there should train ticket station at the airport; if you're flying in to T2 it's on the left, right outside of the baggage hall).
You should have no problem purchasing a Business class ticket, 1st class most likely because it's the first stop out of Beijing.

Would try to buy a train ticket departing at least 2 hours in advance.
Yes BJ West can be a zoo to the uninitiated, so buy the ticket and have it printed out in advance at the airport.

Taking the subway would take 80 minutes, but guaranteed.
You could also try to take a cab, which could be anywhere from 50 minutes to 120 min.

Enjoy!