Considering becoming a passholder - advice needed

[FYI, the first paragraph may not be completely necessary; feel free to skim]

Let me give you the background. I will be 31 next week, am single, childfree, and a solo park-goer. I live in Camden County, NJ. That means it's about a two-hour drive without traffic. For 20 years my "home" theme park has been Six Flags Great Adventure (I grew up in NYC and went to Rutgers before I moved to South Jersey). I've been a Six Flags member every year since 2010. I no longer am a rabid theme park enthusiast like I was in high school (even though I only visited HP a few times as a kid I was glued to the "Keystone Thrills" forum when the rumors were spreading about the project that eventually became Skyrush) but I still enjoy visiting to an extent especially waterparks. Over the past few years I have lost fondness for Great Adventure partly due to boredom, but I also have grown to resent the SF corporation with the chaperone policies that are now in effect at many parks. Even though it doesnt apply to me personally I know it would've been very difficult for me when I was a teen (also my parents probably wouldve found it a drag) I find it very sad that they have resorted to such unfair policies. Not to mention the forced locker rentals you'll sometimes find. Overall I feel Hershey has a much fairer approach to managing conduct and safety. Also I prefer the ride catalog in the candy-themed park.

I admit that may have been a bit of ranting and rambling. The question is, how often would I need to visit to make a pass worth it? I'm planning to go next week but this time I think i'll just get a ticket since they're on sale. Late in the year do they often have a "buy next year's pass, get the rest of this year free" deal? Maybe around candy lane? I could see myself visiting twice a year, not so sure about three. If it was three maybe it would be once in spring, once in summer, and once for yuletide. I know the cheapest variant of the pass only gives half off parking. Are there any benefits at Chocolate World associated with the passes?

One more thing: I am a Costco member. Does that affect the decision in terms of discounts?