Depends where you're going in Tysons. There are metro buses that go to the mall and there is a park & ride off the toll road just before 495 (my mind just blanked).

You can take amtrak to Union Station or the VRE to Alexandria (or Union Station) ... from either take metro, then a bus. Which metro stop will depend on which bus you end up using. It might be east falls church. If you want to taxi from the metro, most likely dunn loring is the best stop as you can go the back way into tysons.

As mentioned above, there is no great way to do this

www.wmata.com is the website to use ... beware of rush hour only routes