He can only listen to the Sony walkman with headphones or earbuds. Walkman does not have capability for speakers so NO Speakers. Yes it does have a track number viewer. And when you stop the CD or turn it off, it starts in that exact same place when you turn it back on.
It can be carried in a large coat like pocket, but there is a holder available (for purchase) to carry it on you without a pocket. I didn't buy one, so I can't tell you any more about that. I can tell you that I couldn't find a Sony Portable Walkman anywhere in stores.
Yes . there is a AC port for an AC adapter. It is located on the outside rim of the D-EJ011 opposite the green rimmed Audio output. It is yellow rimmed.
The proper adapter is available from Amazon. REW
I don't see why not - just plug it from the headphone jack area of the player itself into the auxilary plug-in to your SOLE treadmill speaker system (IF you have an auxilary-in on your SOLE treadmill speaker system).