The Old Town San Diego State Historic Park (corner of San Diego Ave. and Twigg St., 619/291-4903, www.parks.ca.gov [1], daily 10 a.m.–5 p.m., free) makes a great place to start exploring the history of California’s first town.
The visitors center sits in a house first built in 1853 as a family home and set of local offices by attorney James Robinson. Another major home, the McCoy House, was built in 1869, excavated and reconstructed over the years 1995–2000.
Move on to the early 19th-century Mexican pueblos, including La Casa de Machado y Stewart; this adobe structure contains many artifacts that would have been part of the daily life of San Diego [2] citizens in 1821–1872.
Out and about in the park, you can enjoy period music, pet the burros, and observe the park staff engaging in activities folks might have done 150 years ago. Wednesdays are living history days, and the park hosts many events over the course of each year.
If you’re more into the afterlife of the residents of Old San Diego, you can visit the El Campo Santo Cemetery—the oldest cemetery in the city. The park also includes a number of known haunted sites, including the Robinson-Rose House, Casa de Bandini, and La Casa de Estudillo.
Links:
[1] http://www.parks.ca.gov
[2] http://www.moon.com/destinations/california/san-diego