It has been my experience, since I only live about 10 minutes away from PGA and spend a lot of time there, (and used to work there), that during the season it's best to go during the week-Monday thru Thursday. Monday, Tuesday, Wednesday are generally "light" days. <10-30 min wait for Invertigo versus 45min to an hour or more on the weekends and Friday, for example> Too many people there during Friday-Sunday, it makes waiting in long lines to go on short rides not worth it. But towards the end of the season is probably the best time to go as the crowds start thinning out. And and hot days, lookout! Boomerang Bay gets slammed!.
-It's worth the trip, for the few coasters it has (minus Fizzly) Drop Zone, and a few other attractions, the park itself is beutiful and well maintained. Whenever I need a quick coaster fix, I'll just pop over there for a few rides before work.
Be warned, Vortex is a real head banger.
Hope this helps.