I got doored in 1987, commuting to work in San Francisco, going down the Hayes St. hill at high speed. I was not even very close to the parked cars - a guy in a pick-up truck with a long door threw it open and clipped the side of bike just as I was passing by. (Pretty sure it was unintentional.) I went flying down the hill, fractured wrist and some scrapes, amazing it was not worse. My Schwinn Continental was fine and I was able to ride in to work. It was great being young and invincible. Anyway, I think you are right to be worried about parked cars. If you cannot avoid the door zone (which can be larger than you might expect), it's probably best to ride slowly near parked cars.