Mike Allex & I did this route in warm Fall weather - thank goodness for the shade. Thanks so much for posting this route description!
We managed this route with a 55m half rope, 4 slings, and a couple of 1/4 to 3/4 inch nuts (a micro cam in that size range would have been used), but it required breaking the rappel in two. A 60m rope wouldn't quite make it either, in my judgement, but a 70m might.
In the upper canyon you generally stay south of the wash. In the lower canyon, boulder hopping in the bottom of the wash usually works.
Penelope May and I spent 4 wonderful days in the Arizona desert photographing the incredible carpets of wildflowers, roaming the desert and climbing Signal Peak from Palm Canyon via the Rusty Baillie route. It took us 9 hours to get up the route and down, back to our car. Penelope has been on this route before in 2000, got rained off from the friction pitch at the headwall. This time she led both pitches in clear, warm weather. The summit views are awesome. Kofa Pinnacles, Castle Dome Mountains, desert ridge lines south to Mexico and west to California, the wast expanse of desert landscape, what a wonderful place.