I did end up buying the year family pass at Peacock Springs. The ranger was quite friendly and responsive. But it was sort of a funny way of going about things. I went to The Dive Outpost to inquire on the process. The helpful shop worker (sorry I can't recall her name) said she'd ring him up on the phone. At the moment she called he was having lunch, but said to keep an eye out for him after 1 PM in the park - to look for his truck.
Sure enough, just after 1 we saw him pull up near Orange Grove parking area. We walked over and chatted with him. It was about $80 give or take a couple of bucks for the year. He said the pass was good for 8 folks (all divers if need be). I told him that I would be with my brother and have his family and mine, heck one big family. He said no problem, told me to put the card on one dashboard and the receipt on the other dashboard (we had 2 cars).
So we definitely got our money's worth. Went to Peacock thrice and Troy twice. This was for 6 divers and 1 non diver. Although not free, this is about as good of a deal as I'm likely to ever get for my diving dollar. To sweeten the deal even more, the Dive Outpost would top off our tanks with nitrox by the cubic foot (ex. take a 80cf tank from 2500 to 3000 for around $2). I can't wait to go back; I think I'll do an Intro to Cave next time in the area (have cavern already).