Treadmill iPad Desk
With a book holder for the iPad (hooked over the top of the treadmill's console) and a bathtub shelf to hold the wireless keyboard, this becomes a makeshift walking desk. This keeps the iPad at a comfortable angle for viewing and the keyboard at *almost* the right height for typing. I'm not tall so it would be nice if the keyboard was a bit lower, but it's not bad. This set-up also felt far more stable than trying to use a laptop on the shelf.
When I'm ready to do some running, I just move the shelf away and then I have plenty of room for long strides.
Treadmill: Horizon T101 like this one - amzn.to/s5517L
Book Holder: amzn.to/tMYVA7
Bathtub Shelf: amzn.to/upTJ13