The ubiquitous double-decker buses will play a big role, with 17 bus routes passing through Stratford Station. From Central London the No. 25 bus, which you can catch at Oxford Circus (at Regent and Oxford streets), is the most convenient. Buses run every three to five minutes during the day. Plan on at least an hour for the ride, which accounts for traffic. Although the Tube is faster, you'll get the lay of the land on the bus.
Docklands Light Railway, a light rail system that opened about 25 years ago, serves the Olympic Park area. There will be extra trains in the late evening to help with departing crowds.
A high-speed Javelin shuttle service will run between the Olympic Park Stratford Station and King's Cross St. Pancras station. It will run eight to 10 times an hour.
One of the most relaxing and fun ways to see the sights — the London Eye, the Royal Naval College, St. Paul's Cathedral and more — is from the river on a Thames Clipper. Because the river twists and turns, you'll also understand why London developed as it did. These high-speed catamarans run every day at 20-minute intervals. They connect piers near Westminster Bridge (across the street from the Houses of Parliament) and the Royal Arsenal at Woolwich. The stops at the North Greenwich Pier are near the equestrian and gymnastics sites. Extra boat services have been planned and should coincide with dedicated events at nearby venues. Info: http://www.thamesclippers.com