Done solo on Oct. 6-7, 2020, going clockwise. I started at the Cherry Street Trailhead for Mt. Jumbo, running through the neighborhood to the Waterworks Trailhead, basically because I didn't want to run uphill at the end of a 60+mile day. Done this way, the last reliable water source I encountered at this time of year was at about Mile 35, when the East Fork trail starts to move away from Rattlesnake Creek on the way up to Mineral Peak. The last water I saw that might have been enough to fill a water bottle was at Mile 36 or 37 in one of the drainages on the southeast flank of Mineral Peak. I did consider driving/biking/hiking in a cache of water and food to either the Mineral Peak Trailhead or the Sheep Mountain Trailhead, which I think are viable options and would be a smart idea in warmer weather, but I decided to just attempt it unsupported on Oct. 6, 2020. I started at 8:05 a.m. Oct. 6 and finished at 2:15 a.m. Oct. 7, and would have definitely tried to get an earlier start had I not been so foolishly optimistic—I spent a little more than 6 hours running and hiking in the dark.
Water sources I used:
- Rattlesnake Creek (under the bridge on Sawmill Gulch Road just before the main Rattlesnake TH), ~Mile 6.0
- Little Lake, ~Mile 24.6 (about 500 feet off the trail)
- Rattlesnake Creek, ~Mile 32.0 (the creek parallels the Main Corridor trail for a long time; this seemed like one of the last opportunities where it was close to the trail so I stopped to top off bottles, not knowing I'd have another opportunity in 3 miles)
- East Fork Rattlesnake Creek, ~Mile 35.0 (the trail parallels the creek for several miles leading out of the Main Corridor; this appeared to be one of the last easy-access spots to get water)
- There may be more water access a little further up the East Fork drainage—I crossed a small stream at either Mile 36 or Mile 37. It was not super-inspiring on Oct. 6, but I think would have been usable, and earlier in the season would probably be a good water source.
- As I mentioned above, I believe a water cache placed near the Sheep Mountain TH would give you the ability to refill water at approximately Mile 47.5 instead of going the last 30 miles without a water refill like I did.
(Editor's Note: excellent full length report here: https://semi-rad.com/2020/12/the-year-of-making-your-own-fun-run/)