I'd say that besides for Radiator Springs Racers, most FastPass distribution areas are pretty much right next to the standby entrance or directly behind you if you are facing the standby entrance.
A couple FP distribution sites that might not be immediately obvious are Star Tours (across the way, to the right of the entrance for Buzz Lightyear Astro Blasters) and Autopia (across the walkway, under the roof of the Innoventions building).
And don't forget that just because an attraction is listed under the FastPass list, the FastPasses might not be in operation that day (especially if the park is less crowded).
The FastPasses for Radiator Springs Racers typically run out 60 to 90 minutes after park opening at California Adventure. Even though the distribution area is at the entrance for A Bugs Land, you will probably enter the line near the entrance to the Cathay Circle building in Buena Vista Street, or if you get there right at opening, the end of the line will extend into the Hollywood Land towards the Hyperion Theatre. The line moves pretty fast, though, because it's probably a minute or less for each party to get their FastPasses.
I've never noticed the FP distributions located on the maps, but like the others have said they are close to the attractions with the exception of RSR. The World of Color FP distribution is also in an odd spot.
FP for Star Tours is across the walkway next to Buzz Lightyear.
FP for Splash Mountain is right next to the ride across from the Hungry Bear, if I remember correctly.
FP for Indiana Jones is in between the queue and the queue for Jungle Cruise.
FP for Big Thunder Mountain Railroad is next to the queue entrance.
FP for Space Mountain is next to the queue entrance.
FP for Roger Rabbit is next to the queue entrance.
FP for Soarin' Over California is next to the queue entrance.
FP for Tower of Terror is next to the ride in Hollywood Land.
FP for Radiator Springs Racers (RSR) is by the Bug's Land entrance.
FP for California Screamin' is next to the queue entrance.
FP for Goofy's Sky School is next to the queue entrance, I believe.
FP for World of Color shares the Grizzly River Run distribution next to the ride. To get the WOC FP you go in the morning when the park opens. There are a lot of signs that point you in the right direction.
If you want a FP for RSR I suggest making that your very first stop. I was there in October during the Magic Morning early hours and the line for the RSR FP already extended past Carthay Circle toward Hollywood Land and the return times were already past 4pm.
Im sure that you not going to have a problem finding them. RSR is the only odd on out. They are generaly before, across, or next to the general enterance. There are signs to indicated were at each of the attractions.