And how does pack weight effect that time?
I have been trying to get an estimate of the time it would take to get from one location to another in the park.  A big part of that is the time to do portages.  How much difference in time difference is there between crossing with a pack and the return trip. So to find out how long a portage would take I timed my self while walking my dog.  I wore my GPS and found that the rout I take is 2.69 miles.  The course crosses a couple of ravines and has 2 large hills to clime. About half of the rout is un trail woods. It is easy walking woods but not like a path or trail. I started with no pack and then added a pack and progressively added weight.  I changed packs in the middle of the test because I thought the other pack carried better.  
Pk WT Lb.       Mi      Time Min            
0                 2.69      55            11/14/09
24                 2.69      59            11/15/09
45                 2.69      74      Raining& stopped 2 times to adjust
                                               BluePack      11/26/09
45                2.69      77      Wet but dryer than yesterday. Green pack fits better But Compresses chest      11/27/09
57                2.69      76      Better adjusted pack Dryer than last time      11/29/09


Although a heavy pack slows me down it is not as much as I would have thought.
MagicPaddler