Considering your budget:
Either entry fees for both of you at a driver training event track day at Laguna Seca Raceway. Helmets are usually provided.
https://www.weathertechraceway.com/calendar
Or, a track day for him followed by dinner at Nepenthe, then overnight at a cabin in Pfeiffer Big Sur SP.
https://www.nepenthe.com/
https://www.parks.ca.gov/?page_id=570
The next day drive south on Hwy 1 to visit Hearst Castle and return home.
http://hearstcastle.org/
Experiences that you'll both remember forever.
Happy Anniversary!