It's an interesting idea, but I also have a few reservations that I'd love to hear people's thoughts on.
For one, I'm worried that setting the Freehold in a theme park would pretty radically divorce it from Sacramento itself. I mean, the city I grew up in had an amusement park by the river, pretty close to town, but it was still not what I would consider "in the city". I'm worried the park would just become it's own sort of city, whereas a Hotel could still be its own territory, but definitely still connected to the city in a very intimate way.
Secondly, there's no precedence. The Four Seasons has a huge history, whereas a Theme park appearing from nowhere would take a bit of a retcon. Like, 'hey, remember that abandoned park by the river? That no ever talked about? Ever? Really? It's that scrap heap right by Tower Bridge! Yeah, it's suddenly magic again, let's go check it out!'
I don't know, feels a bit forced.
But, if you're in favor of the park idea, then just answer me a few questions.
1. How would the park interact with the Blue Note and Edna's?
2. How would it interact with the City?
3. What role in the park do you see your character play?
4. What would convince your character to move to the park?