Wolftrap is off the Dulles Toll Road (so if you have an EZ Pass, bring it - or rent a car with EZPass, or carry some money with you if you take the Toll Road route). I believe you can get there via Rt 7 as well.

Based on your location, something in Tyson's Corner are would be best - but if you have to choose from those hotels, I think that the Chain Bridge Road would be your best bet - but I would see if the RI Tysons Corner, the Marriott Tysons, Fairview Park Marriott, or CY Dunn Loring are available for your stay. I think the RI would be best for a longer stay as it's basically designed for that.