Thank you for the replies, everyone, as well as the info on what you already know is out there. I knew there had to be something similar, but I hadn't heard about it.
Here are some thoughts on one I'd like to start, taking into account questions you've raised and/or suggestions you've made. Looks like it will a little less intense than that Sniper Adventure challenge...
It would certainly be small to start. I know a lot of people with a lot of land and varied terrain in Colorado that would work well. Hilly terrain that would provide adequate backstops that could make possible a course that doesn't have to be purely linear to avoid exposing anyone to someone else's line of fire. Could also have shooting positions/targets alternate directions so you're always shooting away from where someone could be.
As was mentioned by MCHOG, logistics could be a bear, but I think manageable. The starting point would be away enough from where everyone would congregate so no one would see a shooter leave to the first position, and the direction that people finish in could also be located elsewhere. It wouldn't be too hard to keep those waiting to go away from the start and finish and set the course so that the terrain will mask everyone's movements. We'd have a guy that would act as an RO/scorekeeper just move with the shooters from point to point. That would probably take care of any potential GPS issues, and he would have SA on what the course's big picture is. If anyone was way off the proper heading or overshoots their next position towards a shooting lane, he could give them an assist before they reached a potentially dangerous area. He'd also call hits, which would be on painted steel and easy to tell. If you miss, the penalty is X number of seconds until you can fire again, which would be timed by this RO/scorekeeper. With variable conditions, that would make it really important to make the first one count, since you aren't moving until you hit. These RO/scorekeepers would cycle so they can rest. I think about three or four fit guys moving with little weight should be able to handle it.
Time-wise it would be done over a weekend, and each guy would have a scheduled time to go that would be determined randomly. Maybe a Saturday and Sunday morning so that hopefully no one gets totally boned by afternoon winds, or have everyone go in the afternoons so everyone has to deal with the wind. There could be a smaller course to shoot or some kind of pistol comp to do on the opposite day of your rifle course, as well.
And an awards party at the end, of course...
I'm from a ski town in Colorado that has stuff going on every single weekend from Memorial Day to Labor Day (without covid-19, that is...) There's a Mustang rally, car racing, balloon festivals, whitewater festivals, concerts, etc... I'd like to schedule it during one of those weekends so that during everyone's off time there's a nice place to go and stuff to see and do when you're not shooting or hanging with the other shooters. If the right land could be arranged, shooters could have the option of camping in one area where all the meetings would take place and the party would be at the end.
Thoughts?