Hi Steven,
Donna is absolutely right about Dulles not being a convenient airport for DC. But it is not impossible to get there via public transportation. The trip would take about an hour and would involve a bus and two metro trains that would bring you to Union Station (5 minute walk or short cab ride to the Hyatt). Here is a link for the DC Metro system (
http://www.wmata.com/). You can use the trip planner to plot your trip from Dulles Airport to Union Station, it will cost around $8.00 each way.
Hope this helps!
