MY biggest suggestion is to ride the Metro first thing.
Metro is the parks in-park transportation system. (A monorail). To catch the Metro, take the first main right as soon as you come to the big intersection right inside the main gate, and head straight ahead. The Metro station will be on the right hand side of the path. Ride it one stop. Deboard the monorail and head to the left. You can catch Riddler's Revenge, Batman, Goldrusher and Colossus before most folks even FIND this part of the park.
Starting with Superman also sounds like a good idea, as the line for that seems to crawl (the line inside the Ice Cave is very short, but seems to move faster than the line outside. If you've never been to SFMM be warned that when they call the section of the park that Superman, Ninja, Dragon Pizza, ad the Oriental Garden "Samauri Sumit" they AREN'T kidding. You will feel like you have just climbed a mountain unless you take advantage of the Incline Railway "Orient Express" (And that is to the left of the main hub by the main gate. Look ofr it by Revolutions loop. Snag Superman and Ninja and be done with the summit, then brreze down the mountain to hit the coasters in the rear of the park.
As others have said the coasters in the FRONT of the park are short waits by mid-afternoon. This worked for me when I had the misfortune of visiting the Mount when ever High School in a 1,000,000 mile radius of SFMM was having Physics day there.
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David Bowers
Mayor, Coasterville