Solution: add chickens. They'll periodically jump up onto the arm of your chair to see what you're doing, thus startling you awake from your nap and reminding you to do some work before you doze off again.
In all seriousness, in the 9.5 years I've worked from home, I've spent 99% of that time indoors, even on super nice days. The problem? Neighbors. From the kids playing in a backyard to the neighbor mowing their lawn, then edge trimming, then leaf blowing, I've found the QRM (man-made noise) to be annoying enough that most days I don't bother. And you can count Thursdays right out; that's when the garbage truck is in the neighborhood.
It's the primary reason I'm on the hunt for property outside of town...
Nah, this is why I can't work outdoors. It's hopeless.