Hey Koffee. I have a car but am trying to figure out the bike commute thing too but from Aspen Hill, MD to DC. Two sources of information that I've checked up on in the past week: Washington Area Bicylcist Association (WABA) and Bikewashington.org. WABA's website is waba.org and their phone number is 202-518-0524. WABA is a strong advocate for biking and can assist you with your rights as a biker. I called a fellow there and he gave me some good info and suggestions for biking routes. He turned me on to the ADC Washington Area Bike Map which shows trails/safer roads to ride and can be picked up at most bike shops. The second source - Bikewashington.org has some good online maps of trails and has commuting routes from certain areas.

And careful Koffee with night riding as a lone female. We want you healthy for a long time. Something to consider Koffee... You may or may not have noticed but all the buses in the DC area have bike racks on front. They have to be pulled down in order to load your bike. They are not hard to use and quick after your second or third time using. At certain times you may wish to do part of your trip by bus with your bike in tow. We also can take bikes onto the Metro train during non-rush hour times. I've put my bike on bus racks and taken my bike on the Metro without problem. I wish you well.

Peace and blessings!