I agree with FG, here are the comments I submitted.
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It appears that in effect what you are doing is turning dispersed roadside camping into a developed campground - close-together numbered sites of limited size with amenities (toilets, trash removal, fees). Perhaps there is more demand for this than existing developed campgrounds can accommodate, but I suspect that the current users of this facility will instead look for dispersed camping elsewhere (legal or not).
It should be remembered that one reason for originally creating this area was to concentrate and manage dispersed camping. Back in the 70s the first 3 miles of the Wilderness Trail were a real garbage pit, but banning camping there worked because the Tripoli Road area was established where those sort of users could be managed close to the road. Before implementing this project, an alternate dispersed camping area south of the notches with capacity for half this area (say 250 paot) should be identified and prepared or present users will gravitate to other areas (legal and illegal) on their own. Consideration should be given to retaining those existing sites where adequate off-road pulloffs exist - if these tend to fill first that will show what users are really looking for.
As for tree trimming, preventative removing of dead and diseased limbs is a good idea but the overhead canopy is a desired feature of this road and healthy trees should be retained.