I'm not exactly sure what you are looking for, but here's what I can contribute:
the old Eau Gallie HIgh School on Pineapple drive is creepy & interesting. The south building is open for business during the day. you can go to the first floor/basement.
From what I hear when I worked there, the bottom was sunk into the ground and hardened. It was designed as a bomb shelter. Although I don't think it's a great idea to get the whole school down to the first floor and make them wait for an all clear since the bathrooms are one floor up. Someone is going to need to pee.
The north side building is closed because of a bee infestation. There are deliberately left access holes for the bees to use. If you stand in the front parking lot in early twilight, you can see the drones returning from their days work. It's like the bee highway.
There are also many stray cats that the building occupents feed, so don't be too surprised if you have receive some purry, furry interest.It would be nice to bring them a snack, perhaps of a higher grade than they usually receive from Meow Mix.
If you are into geocaching, there is a geocache store in downtown Melbourne. It's in the back of the Fire It Up art studio next to Sun Cafe. They have a small display of geocache merch. The owner often goes on little expeditions wearing his adventure hat and his vest of many pockets. It sounds like it is a small but active group.
If you go south on Croton until it ends, on the left side is some sort of mysterious government building that looks like it could be systems for surveillance, comm, upper atmospheric weather prediction of other things.
Be aware that the opposite side of the street is the Hacienda Girls Ranch for troubled girls. The older ones can come and go out of their dorm whenever the wish. Be prepared to defend yourself from serious flirting, attention-seeking behaviors, and requests to go buy them cigarettes, liquor or condoms.
Are these the kind of things you're looking for? If not, give us some more descriptors of exactly what you want.