Most listings are in the $20's per square foot per year. The El Paso de Robles region is experiencing a decline in rates. In the last 3 months, the median rate fell $11 per sqft per year. That's a 32% decline in rent.
In the last 90 days, 15 listings have been listed, which means new availabilities most likley are leasing quickly. You'll want to be prepared to make an offer immediately. There aren't many listings below 2,000 square feet posted, so finding a space for a small business might be tough.
The standard measurement for office space in this area is around 1,700 sqft. Most properties in this market are approximately 3 floors.