August 50 miler in N. Arizona?

The north rim of the Grand Canyon is rather high (9000 ft.). When I was there years ago in July I remember putting on jackets in the evening. I don't know what kind of hiking there is there though. It gets warmer as you head down into the canyon. Be careful. If you go down until you're tired it will be a very long way back up, my outdoorsy family thought we had enough water, we didn't.

This one has always been on my dream list (although some swimming would be required): http://hikearizona.com/decoder.php?ZTN=938

I've also done a section of the Eastern part of the Highline Trail that I enjoyed: http://hikearizona.com/decoder.php?ZTN=757

And you could easily link up the Highline Trail with this one which goes to a small lake: http://hikearizona.com/decoder.php?ZTN=815

Unfortunately, those last two don't go very far from civilization. Any trail in Arizona in August will probably be hot though and could be closed due to fire dangers. Last year, there was a large fire that burned up a lot of Apache-Sitgreaves National Forest.

Hopefully some one will post who has more experience in Northern Arizona than myself. If not, hikearizona.com would be a good resource to check out.

Anything around Flagstaff will be nice. You may have 90F days (had a few of those even in the pines this past summer) but there's usually a nice breeze.

The GC is of course sight to see, but the South Rim and down into the canyon will be brutally hot. The North Rim will be nicer but they haven't built a bridge across the canyon (yet) so it's about a 5 hour drive.

While AZ is expansive the terrain lends itself to shorter but considerably more strenuous hikes than most places. Our trails are often poorly marked and maintained with a lot of bushwhacking in the summer.

You say 50 miles, but in AZ we measure distance in units of time (I could go into a whole discourse on this unique and often more accurate cultural peculiarity). I ask this because of our rugged trails. Any of the canyon hikes will most likely have no marked trails and travel will be slower than trail hikers are used to, but definitely worth the effort.

If you want something with easier navigation and better trails, albeit definitely not 50miles, you can do the Weatherford/Kachina trail loop to the top of Mt. Humphrey's. It starts with a 4500ft gain, 10 mile climb to the peak. Come down the shorter snowbowl trail and end on the 9 mile leisurely Kachina Wilderness trail which wanders through alpine meadows, aspens, and pines. It's ~25 miles total overnighter. Just be wary of afternoon lightning in August if above treeline.

Another point is water. Unless you're following a perennial stream, you can pretty much count on there be no water on any hike you do in August. Most of the seasonal streams would be long dry after summer (and with no snow this winter…). So your pack weights skyrocket just from every 8.8lbs/gallon/day you'll be lugging around.

Hikearizona.com is a great source as is the following, except the author is a very strong hiker. I usually multiply his estimated hike times by 1.5x:

http://www.toddshikingguide.com/Hikes/Hikes.htm