I believe its Disneyland drive( I always take that exit but I'm in the carpool lane). But I am pretty sure it says that once you exit just follow the street signs it will take you right into the garage.
Years ago during some preview days at DCA we got stuck on California screamin right after the loop we were pretty high up, I had pushed my lap bar down to tight and the music was blaring in my ears all while being stuck it was about 40 minutes until they had to come and walk all of us down...I've only been on that ride once more since that day!
This is my FAVORITE ride at DCA because I always feel like I have escaped death every time I ride it and the car doesn't go flying off the tracks on those sharp turns! This would have been the cherry on the cake for the fear factor alone! I love to get scared!