While I was working on last week's post, I gathered rather more information than I needed for something focused on mall redevelopment though most of it is really really wonky. Be forewarned.

While working through Corte Madera's zoning code (Title 18 of the Corte Madera Municipal Code), I found that the densest type of zoning is R-3, which allows 17.7 units per acre at most but still requires buildings occupy at most 35% of a given lot, meaning an effective floor-area ratio of about 1. In these zones, even studio apartments need 1 parking space each, and one parking space is needed for every 10 housing units to accommodate visitors.
As far as I could tell, there aren't any parcels zoned for R-3 in Corte Madera. R-2 is rather more restrictive. It allows only 10.8 units per acre.
The minimum amount of land needed for a parking space in Corte Madera is 204 square feet. The minimum size of a studio apartment in the state of California is 160 square feet.
Corte Madera precisely prescribes the types of uses allowed in any given type of commercial space. One can't, say, open a bookstore in the along Tamal Vista (zoned C-3), sell electronics parts downtown (C-1), or sharpen tools in a store at Town Center (C-2).
The number of units per acre in downtown San Anselmo, including the Flats, is about 15.5. If you want to live downtown, nine stores (zoned San Anselmo's version of C-2) can have at least one apartment above. One of them, the shingled building on San Anselmo Avenue between the Courtyard and Bridal Salon, has three. Unlike Corte Madera, it's legal to live above a store in San Anselmo.
The best tools I've found so far are MarinMap's Geocortex and the county assessor's Property Tax Inquiry. The standard MarinMap is pretty handy, but nothing beats the querying capability of Geocortex. Find out the zone, size of buildings on the property, address, parcel number, and just about anything else you wanted to know. For the rest, you'll need to input the parcel number into the Property Tax Inquiry, which tells you things like the number of housing units, how much they pay in property taxes, and more.