For this effort, I followed the GPX tracks of the unsupported FKT holder, Corin Kwasnik. At 5:45am, my friends Andy Boyle and Calen Henderson drove me to the footbridge connecting to Coconut Island where the GPX tracks start. In retrospect maybe we should have crossed the bridge and actually started on Coconut Island though, because I believe the island has a public bathroom (?), which would have been helpful.
Together, Andy, Calen, and I did the ritualistic dipping our hands into the water. Then I started running at 6:03AM with 2.5-3.0 liters of water and covered the first 36 miles solo. Of the 36 miles on pavement, the first 30 were easiest, and I maintained an average pace of 9:43/mi (a little faster if we exclude snack and pee breaks). Still, I wouldn't say the running is easy. You're ascending 6600' in altitude and there are a couple punchy miles in there, especially around mile 20 where the grade briefly picks up.
By mile 30, I was feeling the accumulated fatigue of a 30-mile, 6600' grind and my stomach was unhappy with 2000 calories of sugar water bouncing around. I made the decision to walk the hills and run the flats. I only averaged 14:50/mi during this 6-mile segment. If you've still got any juice in your legs, these miles are a great opportunity to cut serious time off my effort. They're hard miles though, I believe there's a brief bit at 17% grade.
The ranger's station at mile 36 currently has regulations that you need to fill out a form, spend at least 30 minutes at altitude, and talk to the ranger before hiking up the road. I was glad that my friend Andy Boyle was waiting for me at the station, and he had pre-filled out the form for me. Even with Andy's help, it took 8.5 minutes to refill water, wait in line to talk to the ranger, and get moving again. I believe these new regulations make it harder to do the Mauna Kea route unsupported and they add 5 minutes to the total time.
During the last 8 miles from ranger's station to the summit, I hiked well and was able to run the flat sections. I carried my own water but Andy was hiking at my side. When I was feeling slow and weak, Andy kept up an even pace. When I was strong, especially over the last two miles, I led the charge and Andy was my faithful sidekick. I have never been supported on an FKT effort before, and I would recommend it! We both made it from the ranger's station to the top in 2:21:50, which represents an average pace of 16:46/mi.
In conclusion, the Mauna Kea route from Hilo provides a wonderful opportunity to tour the big island and see its distinct biomes, from the lush lands around Hilo to the desolate moonscape at the top of Mauna Kea. The route covers the greatest range of altitudes I have experienced in a single run. Moreover, I expect it is the most runnable route in the US that covers such a wide altitude differential.
In terms of overall performance, I am happy with the effort but do wonder what additional accelerations would be possible if (a) my friends carried my gear for me, or (b) I was able to contribute a stronger effort from miles 30-36.