There are several non-urban properties listed above. Do not hire a car, let a local TA or The Vines make your reservations for tasting and a remise with driver. On your own in a car is practically impossible, local car (remise) and driver gets you to the wineries that you will never find on your own.
Posted from the Sheraton Quito, PM me after the 20th and I will be happy to help with telephone numbers. web addresses and other questions. Some are posted in this thread.