When you run test map, if player walk thru the trees, if you walk looking to the sky, you gain fps (stop calculations?), but it you look to the trees, fps drops drastically.
I thik the best way is GG taking care only about the items in the scene.
I believe GG has map divided into areas, and player just can be in 1 area at time, so just load the items placed in that area, and take care about them,
If player interact with some item than cause changes in an unseen item, so the script handling this item beahaviour should state it to the ebgine, so engine go to this men aadreess, where this data sit, and update it.
It should be like a theather system, The curtains goes down and everything changes, the curtains goes up, and voila, a new scene, and nobody is thinking about the stuff behind the scenes.
3com
Laptop: Lenovo - Intel(R) Celeron(R) CPU 1005M @ 1.90GHz
OS: Windows 10 (64) - Ram: 4 gb - Hd: 283 gb - Video card: Intel(R) HD Graphics