Found out about this route a few weeks ago and decided to give it a try on my way out to TWOT weekend.
I stayed at the Montebello Campground the night before and drove down to the trailhead parking area around 6:30am while making final adjustments to my pack. I had planned on waiting until sunrise to start, but I got sick of waiting so I grabbed a headlamp and started out at 6:52. I started with 3liters of water and 1 gu flask hoping that would be sufficient for the entire run. I did bring along my water filter "in case of emergency", but I didn't end up using it.
So I started up the AT towards the 3 Ridges. Since this was my first time on the trail, I didn't have a good idea on pacing nor what to expect. The trail was a bit more rugged than I was anticipating but not too bad but the humidity was tough. Despite the 60F temps, I had sweated through my shirt in the firs mile. I figured this first climb was going to be similar to the TWOT opener in length and elevation gain, so I put in a hard steady push up to the top, however, unlike TWOT there were very few downhilll drops to catch your breath. This was just a long hard climb with only one downhill bit.
When I got to the top it was a little after sunrise and the views were great, however, I didn't spare more than a glance and kept on running. When I reached Maupin Fields, I waved to some campers and turned down the Mau-Har Trail. I was thoroughly enjoying the descents and thinking I'd been making excellent time, then I reached the mile 11 climb which I had completely overlooked in my prep. Oof this mile took a good chunk out of that "excellent time" I thought I'd had, but I still managed to reach the parking lot by a little over 3 hours.
I thought I was in pretty good shape expecting the second half to be less time given it was a significantly shorter section. So I started the climb up the Priest expecting it to be hard and slow, but I was not expecting the extended nature of the steepness. At one point I questioned whether I'd be able to make it up and back in under 3 hours given how steep and rugged the trail was. Since, I wasn't going to be able to make up as much time as I had hoped on the descent. Around mile 18 I ran out of water and was kicking myself for not filling my filter at the stream about a mile and a half up the Priest. Finally the climbing ended and I was able to run/breathe again. I went and tapped the shelter and headed back up the trail to the summit.
On the way down, I had to be a little cautious to avoid cramping. I could feel my calves catching now and again, so I opened up my body flasks and finished off the last few drops that I hadn't been able to suck out through the nozzles. When I passed the stream again, I was definitely tempted to stop and refill, but I quickly decided to just keep pushing and reward myself with the Gatorades I had in the car.
I know in less humid weather I could have shaved a bunch more time off, however, for a first attempt I was pleased with my effort. Afterwards talking with folks about my run, they all raved about running in the area and I hope to be back soon.