Lovely idea. Definitely helpful to some readers. I have a particular person in mind that I'd like to buy a copy for. But not so helpful for me, though it could have been.
Execution needs a stronger editor to bring more out from Watts. For example the memoir bits were wonderful, if too short for the development of empathy. I also opine that it could use more specific instructions that make sense (for example the list of gear to bring grows by chapter and pretty soon a person will want a burro to carry it). Also needs a better proofreader: "You may require more equipment than you are unaccustomed to in order to experience more of the environment."
"Mixed flocks of birds are highly efficient communities that capitalize on the differing capabilities and needs of the various species. For example, while one species eats high up in the trees, a different species will forage for food on the ground...." Which??
I do like the tip for preparing for a trip: "Do some virtual bird watching in your target region. You can watch them repeatedly to thoroughly learn regional bird species and enhance your actual bird watching outing. You will sharpen your ability to accurately identify these birds, which will boost your confidence and willingness to go birding an increasingly distant places."
If you're interested, for example if you or someone you know has any reason at all* to be limited to looking out the window, give it a try.
Not just disability, but being in a nursing home, prison, urban high-rise, etc.