I was thinking of how season passes would work under a bigger company.
I wonder if a tier structure based on the number of parks you want to access would work: one-park, three-park, all parks. The three-park pass allows you to pick the parks you want to access, either when purchasing the pass or just "locking" your card after you enter your designated number (once you enter the third park, it only works for those three parks). The mid-level becomes a sort of "regional" pass, but still allows you to make your three parks across the country from each other if you want.