Before taking a road trip to Mammoth Lakes recently, we looked into renting an AWD SUV and it's more challenging than you think. Mostly, none of the major rental agencies will guarantee AWD.
We ultimately just drove our Honda Accord as road conditions were great, but I did discover Audi Silvercar is a good option. Yes, Audi has a car rental operation in a small number of cities. Unfortunately San Jose is not a major city (I lived there recently for 5 years). But if you want to rent an A5 cabriolet, you can pick up from SFO. New users get 20% off. When I looked at it, I saw you get unlimited miles. Oops, the rate for the A5 convertible isn't exactly cheap.
They should have a good discount on Black Friday, so I'll wait until then to plan a one day rental of the Q5 (basically an extended test drive).