Mike, we can easily stash water at the halfway point; this can be done when driving out to the start on the morning of the run.
I can bring a shelter and any other gear you might need so your flight is easier.
If Art and John can pick you up, I could get you back to Palm Springs on Sunday. Not to put it all on them, but I think Palm Springs is more in their travel direction. Regardless, I don't think I'd be leaving any later than 10am on Sunday, staying long enough for coffee and packing up.
I'm thinking the best way to run this is to start at the North entrance backcountry board (start of the CRHT) on Saturday morning and run back towards camp. The CRHT ends at Black Rock; that way people can get in at whatever time/pace suits them.
We can all pile into a car early Saturday, drive into/across the park, stash water, get to the start, and leave the car there. Saturday night or Sunday morning we can go pick up the car; leaving it overnight at the North entrance backcountry board is OK.