Edwin - thank you for setting this up. As previously stated, there are a ton of people in this group willing to work and help. The key is coordinated efforts and someone to be the catalyst and rally the troops. You've taken that catalyst role by the horns!
Now the bad news: unfortunately, the family and I are taking a trip to south Texas from 7/26 through 7/30, and I will therefore miss this trip. If it's any consolation, karma will be punishing in the form of Galveston heat and humidity for not being there to help you all.
If I can offer a few points:
1) That is peak thunderstorm season in that region of the mountains. You'll have a better idea of the weather as the event approaches, but I'd have a plan in my back pocket in the event that storms hammer the area. If they do, it would likely happen in the afternoon hours, between 1:00 pm and 6:00 pm. Just be ready is all I'm saying.
2) Those shooting areas are going to need TONS of work. If you get a big enough group, my recommendation would be to get almost everyone settled in at one (or both) of the shooting areas and start cleaning up while a much smaller team (yourself and at least one other rig) runs the remainder of the trail and performs a survey, taking photos and documenting anything you want the forest service to be aware of. In my opinion, this would be the best use of time, and would prevent a situation where you guys all end up staying in one area too long and then not having enough time to perform an effective survey of the rest of the route, or spending too much time surveying as a huge group and then not taking much action while you have the manpower on hand to help. If the shooting spots do require as much work as we think they will, it'll be a good idea to bring some shade tarps/eazy up style canopies and chairs for everyone to take a break and eat lunch. I have an easy up I'd be more than happy to loan out if you guys need it.
3) To support #2, and since I won't be able to be there for the actual cleanup event, I can go run the trail in advance of the group and report my findings back to you so you can have a solid plan for the group. It's not nearly as far of a drive for me as it is for most of the rest of the group. I won't do a full slow-survey like you're planning, but I can at least visit the shooting areas and look for anything major along the route that will require a lot of work. Other than the shooting areas, is there anything specific you'd like me to check on and report back about? I'm tentatively penciling this in for this Sunday, 7/7. I'll bring my trasharoo and some trash bags and pack out what I can while I'm at it.
4) Pending how bad the shooting areas are when I go look at them, maybe you can ask Greg and the forest service to support with a dumpster. Even if they have one brought to the top or bottom of the trail, it would save the group from having to haul everything back home or to the dumpster at the ranger station or discovery center. Hopefully you guys can get at least a couple of pickup trucks out there to assist. There are usually junk TVs and refrigerators and crap at those spots.