Good luck.

The chances of the site being re-opened are non-existent.

The Forest Service is run by spineless bureaucrats. None of them are going to risk being blamed for an accident if they lift the closure---and more importantly none of them is going to run the risk to their careers of lawsuits against the USFS by the local complainers.

I used to live just outside of Flagstaff, Arizona, and we experienced the same issues: retirees and tree-huggers moving into the woods on the edge of the local National Forest, then complaining loudly about locals shooting, hunting, cutting firewood, etc. The loudest complainers were wealthy retirees who had both the time and the money to make nuisances of themselves to every bureaucrat and politician who had any say in the matter.

The Arizona Game & Fish Department attempted to built a shooting range---one laid out with safety in mind, to be staffed by full time range masters. The NIMBYs took them to court. One site was "too close" to homes---it was miles outside of town and several miles from any existing homes. The next site was "environmentally sensitive" because once in a while antelope had been seen walking across it. Another "posed a threat to ground water resources."

Game & Fish started trying to build a range back in 1996 or so. They're still tied up in court, and in the meantime most of the National Forest for miles in every direction has been closed to shooting.

If this site is a former dump, that might be one way to apply leverage to the Forest Service. Has the dump been properly cleaned up? Seems if the Forest Service wants to "preserve" it, perhaps they needed to have their feet held to the fire by means of a lawsuit demanding that they spend a big chunk of their budget cleaning it up and completely remediating the damage done by dumping? Bureaucrats fear losing budgeted money more than anything else...