I believe that, (based on what you’re saying), the real issue in your project isn’t so much about what gets rendered or not, or at what distance.
The heavier part is probably all the different collisions that need to be checked.
Maybe,and I really mean maybe,you could dig into Pandako’s fast collision system instead of the classic one, just to squeeze out a few more FPS during collisions.
or maybe consider this object culling system
It’s all something that would need to be tested anyway.