R2R2R Run

Getting my gear ready to run the R2R2R (basically running from the south rim of the Grand Canyon, over to the north rim and back to the south rim) this weekend. Still deciding if I'm wanting to go the Kaibab Trail or Bright Angel Trail upon my return to the south rim. The two previous times I've done this run, I've always opted for Bright Angel. Now that it is mid-November and the temps are looking rather "chilly" (my two previous times running this have always been in May) I may just decide on Kaibab.
I'm running with Nathan Spear, an old friend from high school. He and my twin brother battled for the top x-country spot in the Portland Interscholastic League (PIL) back in the early 90's -- while I was sucking wind as a mid-packer. This will be his first R2R2R. He has ran one other run about this same distance, but any one who has run this knows how challenging the R2R2R can be.
We fly out at 0830 Friday and return 1530 Sunday. I'll let every one know how it goes upon my return. Cheers.