Photos on Strava.
I took the Rainbow Direct Route up and down. It is an obscure 3rd, 4th, and low 5th class scrambling route that goes directly up the SE face of Rainbow Mountain. I started at the Oak Creek Canyon TH inside RRCNCA and followed the trail until reaching the mouth of the canyon, then headed up RD. Most of the route is 2nd and 3rd class with multiple 20-30 crux sections that go at easy 5th. The route is littered with hand lines, although I rarely used them, most of the climbing feels more secure then the random ropes. The route is in good shape though as several parties have been up this spring, including myself during the Red Rock Great 8. Check out my youtube channel for more on that one, just search my name: Christopher Gorney.
I went completely solo on this mission. Started at Oak Creek TH inside RRCNCA
1:30:06 TH to summit
~5 mins on summit, very windy! I smashed my finger trying to open the summit register, ouch.
1:03 summit to TH
2:38:56 Roundtrip
I believe this route to be the most direct and fastest to the summit of Rainbow Mountain, granted you know the route well, it is hard to follow and rather convoluted.
I wore a waist pack with one water bottle 500ml and 3 gels
I also had a soft flask in my shorts pocket 500ml
Tank top, running shorts, hat, shades
5.10 Access trailrunning/approach shoes, my go-to for sustained scrambles.