DOC 2 BE -

Hilton-Dulles run their own shuttle bus to/from the airport. I do not have any idea of the schedule or info on the "first/last" run of the day, but they do have their own.
If your wife wants to catch the hotel bus she will have to stand outside and it can be VERY COLD waiting out there. Need a "Yankee" coat for sure.

If the company will pay for it, I would recommend a cab from the airport for sure. NO waiting outside in the cold! From the hotel back in the AM, I have no idea since I rented a car while I was in the DC area.

Good Luck on the trip.

dAAvid -