Santa Fe has a small but vibrant downtown that is not only walkable, but walked, often, by many people late into the nights, particularly in summertime when the tourists flood in. Parking can be a problem during the summer, but look for parking lots fee near St. Francis Cathedral, the new Convention Center, and between Water and San Francisco Streets west of the Plaza. If in town for the Santa Fe Indian Market, plan on parking away from downtown and taking a shuttle, e.g. from De Vargas Mall. Limited, but improving, public transportation is available at other times via Santa Fe Trails (http://www.santafenm.gov/...), the city's bus service. The North Central Regional Transit District (http://www.ncrtd.org/) "Blue Buses" provides free bus service Monday through Friday with routes that connect the counties and communities of Santa Fe, Taos, Los Alamos and Rio Arriba.
The main roads through town are St. Francis Drive US 84/285 from north to south, Cerrillos Road NM SR 14 from the downtown area southwest to I-25 and beyond, Old Santa Fe Trail and its offshoot Old Pecos Trail from downtown southeast to I-25, and St. Michaels Drive and Rodeo Road and its offshoots, both connecting Old Pecos Trail and Cerrillos east to west. Most outlying attractions are accessible via one of these roads. The downtown area is a remarkable warren of small roads that you really don't want to drive on; park your car and walk. Streets there tend to wander Paseo de Peralta, one of the main roads in the downtown area, almost completes a loop and, even when apparently rectilinear, are not necessarily aligned to true north/south/east/west. Take extra care for pedestrians and cyclists, many streets have sharp turns.
If you're bound for the Santa Fe Opera from Albuquerque or points south, consider taking the Santa Fe Relief Route NM SR 599, which leaves I-25 south of the Cerrillos Road exit, bypasses most of Santa Fe, and meets US 84/285 just south of the Opera. This can be a good way of getting to lodging and restaurants on the north side of town e.g. Gabriel's, cited below as well; although it's a few miles out of the way, the much less chaotic driving, particularly around rush hour, provides considerable compensation.
Once you get to Santa Fe, consider taking a tour of downtown. Several companies offer open-air tram tours, like The Loretto Line Tours (http://www.toursofsantafe.com) available in the parking lot of the Loretto Chapel. These tours last about 1.5 hours and give you a sense of the architecture, culture and history of the downtown area.
