I'm following a schedule by Jeff Galloway which involves run/walking. Up to 20 miles on my long runs with a run 8min, walk 1 minute plan. The times are good. It doesn't seem to take so much out of my legs, so I can run faster later on. Worth trying for the long runs.
The sansa express looks like a cheap alternative to the ipod shuffle, don't buy one as the firmware is a nightmare. Just but the shuffle or sansa clip instead and save yourself a load of pain. The id tags are not preserved and it only works when importing music from windows media 11.
I hope this saves you from not playing the albums in order .
I had pretty bad PF, orthotics cured it. Fell Liker is talker a lot of sense, try some superfeet/orthaheel insoles to cure it, or look at the PF queries in this forum for advice. You may need to visit an podiatrist.