How do you (or other people) even get into some of these places? :0
Hiya, thanks for your message and sorry for taking ages to answer!
I’ve never been to an abandoned theme park myself, but I have read about people exploring abandoned theme parks and they usually look for gaps in the fence. Probably some of these abandoned theme parks don’t even have fences around them? You have to watch out for security though because you’re not supposed to explore these places.
I know that Spreepark (Germany) and Land of Oz (North Carolina) had events where they were open to the public. Land of Oz still opens in June and the first weekend of September and October. (Source)