The park has been shuttered since its previous owner, Six Flags, declared bankruptcy in early 2010.
Hart’s agreement was due to expire at the end of this month, but has been extended through September.
Hart has previously asked state and local governments to issue bonds totaling $50 million to finance the redevelopment.
But state lawmakers declined to open the budget in the last session, and Metro Government officials earlier this month declined his request for a $20 million bond issue that would allow him to re-open the park next year, calling it too risky.
Hart came back with another proposal under which he would put up more of his own money, and now is floating another option that he says would involve a funding approach similar to that used for Louisville’s new downtown arena.
Hart says he needs $50 million to refurbish the park in two phases; the first would add three rides and expand the water attraction; the second would bring in a new major roller coaster.