This site is being deprecated.
Please see the official X‑Plane Support page for help.
I am not aware of a plug in but there are all the rendering options you can use to adjust how much detail is in the world. Please check out this section of the manual for detailed info on what each option in the Renderings Options screen does. Please start with the rendering presets and then make individual changes after that.
This site is no longer being actively maintained.