Just completed a R2R2R crossing this past Saturday down at the Grand Canyon.  Here's my report if you're interested in the details.  It's lengthy, so skim for the info.

http://completingbutnotcompeting.blogspot.com/2014/05/grand-canyon-rim-to-rim-to-rim.html

Thanks for reading. And thanks for all the advice that many of you have given over the previous few months.  It was a wonderful adventure, priceless memories, and something that I'll never forget.

Great write up.

AT, I didn't have any problem with orthotic in the 4 weeks leading up to the run, but in retrospect, I guess I'm not surprised. I do remember feeling pressure in the heel from time to time, but I never developed any blisters before the run.  It was a catch 22, I really needed the insert I think for my arch, but it compromised my heal a bit.  I have a post run followup with my doc in a couple of weeks, will see if there's anything he needs to adjust.

As far as the hiking shorts, I wore a pair of Columbia Silver Ridge convertible pants, with the zip off legs.  I wanted to have leg protection in case in got too cool, and also wanted all the extra cargo pockets in the shorts.  They actually worked great.  I wore a pair of compression shorts underneath.  No chafing at all, and had been training in them for about 3 months prior to the run itself.

Congratulations to you and the other two runners, what an accomplishment. I really enjoyed your

report; I felt the heat, I sensed that feeling of knowing whats down there in the dark. I've only been

there once, during the day, briefly, but it's an awe-inspiring place.

Wow, what an adventure and a huge accomplishment.  I've never been to the Grand Canyon so I can't even really imagine what that must have been like.  How are you recovering?

Jamezilla, My legs actually feel pretty good because there was so much walking.  The blister that I had is taking a long time to heal, still hurt today with my shoes on, so no running yet, but otherwise, the legs are ready.

Daydreamer, I think you've set up a good plan.  Do what you can safely do and not get in over your head.

For your questions, the day we ran, it got to about 95 down at the bottom during the afternoon.  Leading up to that of course was not as warm.  As a reference, we left at 320 and it was in the mid 30s. Got to Phantom Ranch about 920, and it was already 70. I suspect by the time you go, it will be much warmer.  You can use this link to get the forecast for Phantom Ranch.  On that page, at the bottom, there are also links for the graphical and tabular forecast, so you can get a feel for how temps would change hour by hour.

I ran out of water because I didn't anticipate needing that much since it's only 5 miles from the Ranch to Indian Garden, so I didn't carry enough.  But it was still hot, even though the sun went down, and I was already fighting dehydration, so I should have filled up, but I left without putting any in my bladder. But there is water at Indian Garden year round.  I don't think you'll run out of water since you're going in the morning.  I could have filtered water out of the creek which you will cross a couple of times going up to Indian Garden too.  You'll also have water at 3 mile and 1 1/2 mile, so carrying 100oz may be a bigger load than you'll need.

You may also find that the climb up Bright Angel could still be shaded, depending on how long it takes you to get down, since it will take a while for the sun to rise high enough to get over the canyon wall.

And I think the trekking poles were invaluable for me.  They helped me going down by distributing my body weight on 4 points instead of just 2, and took a lot of the strain off my knees.  They helped me stay balanced too on uneven terrain.  I also use them going up, helping to ensure that I don't lean forward too far, and they also help push me up the hill if you use them right.

Have a great trip, you'll love it.

Good job! I totally agree about trying to get a rhythm going down that Bright Angel trail. It's a rotten trail.

I'm looking at another attempt late fall or early spring (next year). I'm determined to make it the whole way this time.

Cookie Monster, some of those are valid concerns.  The other two guys are seasoned ultra runners, both have completed 100 milers and have been running for years.  One of the guys has been running his whole life.  And both ran a 50 miler at the end of March, so they were as well conditioned as I.  They just got sick, which slowed us down.  Yes, the not filling up with enough water was my mistake.  By then, it was dark, and I thought it would be cooler, I also knew that water was only another mile up when I ran out.  So maybe it sounded more dire than it really was.   I do regret leaving my buddies in the last section.  The one guy (lifetime runner) was actually feeling a lot better, he wasn't sick anymore, and was taking care of other one, so I felt comfortable enough that it was his turn to get the other guy out.  Those two are best friends, so I already knew that the 1 guy was taking care of the other one, which I guess I didn't mention in the report (I should add that, because it is important).  I feel we did make smart choices though.  You adapt to the situation.  When the guys got sick, all time goals went out the window.  Survival became more important.