With six lanes, going east-west, Lombard St is the main road and considered along with north-south Van Ness to be part of Highway 101. The winding section of Lombard St is due east, on Russian Hill.
This is a fantastic area to either walk or cycle through as it is predominantly flat with the obvious exception of Pacific Heights, and also because it's a very safe area. Given the area's popularity with joggers, walkers, power-walkers, and cyclists, you will definitely not be alone. Chestnut St is the business section of the Marina and considered among the poshest of San Francisco's streets. Union St and Fillmore St are the other two main shopping areas in this district. To the north, along San Francisco Bay, runs the 74 acre stretch of Marina Green. Your walk can continue along the bay to the west, through the Presidio, along the restored Crissy Field marshes, all the way to the Golden Gate Bridge; or to the east, a short climb through Fort Mason and down into Fisherman's Wharf.
If you are interested in biking around the area — "biking the bridge" is very popular activity — there are several companies that rent bikes out to tourists by the hour or for the day, including Bay City Bike (http://www.baycitybike.com/), Bike and Roll (http://www.bikerental.com/), and Blazing Saddles Bike Rentals (http://www.blazingsaddles.com/).
