This sounds like a good idea, and I'll try to attend. Lee-Jackson-King weekend is probably no good for me either, though.
yanky, I've been to two outdoor ranges. One was a commercial range used for the TFL meet in PA. There they have shooting benches for the rifle range and (I think) tables for the pistol range. I'm not a big fan of benches though, since they seem to be in short supply out in the field.
There everyone walked to change targets, even to the 400-yard targets. The other was a private 25-yard range used for the LFI class in Richmond. That was basically a berm with plywood target stands, and tables at the other end for range bags. The instructors would pace off the distance, then everyone would stand in a line and shoot. Based on that experience, have some spare wood and a hammer in case someone shoots the target stand to pieces.
Usually everyone shoots at once, then they pause and go change targets or whatever. As long as the firing line is clearly marked and everyone stays behind it, and nobody touches a weapon during target changes, this seems to be perfectly safe. I don't know how many target stands you'll need, but several for the 25 yard range and maybe two (depending on how big the stands are, and how many targets they hold) for each of the longer ranges should be plenty. People can bring their own tables if they so desire; I'll be bringing one anyway as part of my CR-V.
Herding cats is an appropriate title. Based on past experience, expect no more than 2/3 of the people who say they'll attend to actually show up.