Two weeks in the Canyon is a long haul. They key is to find a route that doesn't have you going up and down every other day as Canyon hiking can be very rugged. You can do a number of routes that will put you close to two weeks without many challenges with water. A popular longer route is to hike the Tonto Plateau traverse, but it gets boring. I do like to use the Tonto to link other trails. In the Canyon, hiking East/West is almost always done on the Tonto Trail along the south side. I traversed the north Tonto in '97 and since it's a "route" and not a "trail" it was 16 days of the most rugged hiking of my entire life. The southern Tonto is the ticket.
For example you could head down the New Hance which is 20ish miles East of the village. That takes you down to the river. From there you hike up onto the Tonto Plateau with water at Horseshoe Mesa (9 miles away), Cottonwood Creek (4 miles further), and then Indian Gardens another day away. From there you could go down to Phantom Ranch, do a side trip up Phantom or Clear Creek, maybe up to the North Rim, etc.
Caching food in the canyon is tricky. Protecting the food is the biggest challenge as mice eat through everything to get to food. My previous caches have been done with the okay of the park service as I was doing water surveys at the time, so you might double check with them about food caching. If they green light caching, you could cache at Indian Gardens with a short day hike before you start. I know some hikers have sent caches down to Phantom by mule, but again you'd have to arrange that with not only the park service mule service but the independent operator at Phantom Ranch.
Mileage in the Canyon is tough mileage and everyone tackles different daily distances. Last year a buddy and I did a loop in 3 days. We met another group doing the same loop in reverse in 5 days. So, much depends on how far you want to travel per day. I'm of the opinion that 12-15 miles along the Tonto is my max, but it is relatively flat walking. Going down I can handle 7-12. Going up is about the same.
It's an amazing place. My hands down favorite places are (google images): Hance Rapids, Horseshoe Mesa/Cottonwood CREEK, Phantom Creek, Thunder River, the South Bass Trail, etc. I've hiked over 1000 miles down there starting when I was 5 in 1976. Never gets old.
