If your cave has many twists and turns that completely obscure an actor, you should not worry, the engine is already culling those actors for you.
Check out the list of console commands to see how you can test this yourself, but I’m fairly confident the engine is already handling this for you exceedingly well
I would like to add that those will still be loaded into memory even if not drawn. If you are working with an MMO you wouldn’t want some things to always be. Think of dynamic spawning loots that can be relocated etc based on some criteria during runtime. The engine will not draw them but I think it will still load them. If you enter a new area it would be good to load resource sinto the client’s memory based on the current disposition of things within that area.
Now within the editor I know you can associate actors with a level. Here that solution might work if you can do that in game as well. Do you know if that is possible ?