Always look at the wait time for the standby line too.
We have been to AK during Spring break (when it is very busy) many years and have found that many of the attractions at AK have short waits in the afternoon. Since most people come to AL early in the morning and leave by early to mid afternoon, you can often walk right on in the afternoon.
The Spring, part of our group went on Dinosaur without fastpasses with just 15 minutes wait in the standby line. We also went on the Safari (as fast as you could walk on for ambulatory people - a wait for those who needed the handicapped tram).
We had Fastpasses for Kali River Rapids, but after using them, members of our party went on that ride 3 times in a row, pretty much as fast as we could walk thru the line.