Some statistics for the trails we'll be hitting:

• South Kaibab Trail - Trailhead (South Rim) to Phantom Ranch - 6.9 miles, dropping 4,700 feet
  
• Bright Angel Trail - Phantom Ranch to South Rim Trailhead - 9.8 miles, climbing 4,330 feet
  

I have a little spreadsheet breaking the descent in and the climb out into five and six segments respectively, with the following statistics listed for each segment:

• cumulative total distance from start
  
• elevation (feet above MSL)
  
• segment distance (miles)
  
• segment elevation change (feet)
  
• segment percent slope
  
• segment run per foot of elevation change
  
• cumulative total elevation change from start (feet)
  

If you are interested, let me know and I will send you a copy of the spreadsheet!

A couple of books to consider before March!

The Man Who Walked Through Time by Colin Fletcher, about his trip, the first ever, walking through Grand Canyon below the rim. He died this past year, in June, at 85.

Grand Canyon: Solving Earth's Grandest Puzzle, by James Lawrence Powell, a 2005 publication about the recent scientific consensus on how Grand Canyon came to be.