Parking is not bad if you are willing to pay, there is a large parking structure adjacent to the testing center building (very close to the Levi Plaza).
The building is actually very easy to find and is right off the embarcadero near Fisherman's Wharf. It is easily accessible from the Bay Bridge, or Golden Gate. Google Map that and you should be good to go.
Once in the testing center you will be placed into a single room where up to 15 other people may be taking similar exams. Lockers are provided and a bathroom is nearby. I give it a 7/10 for convenience. Noise levels are very low, which is a good thing.