What about a visual chart that you can hang somewhere prominent that shows your daily schedule? Something big and colorful with a very general schedule that the kids can help you come up with. I'm thinking of general categories like Breakfast, Getting Ready, School Time, Outside Fun, School Time, Lunch, Relaxation, etc. So, when middle child says he doesn't want to go outside, you just respond with "The chart says it's outdoor fun time!" and it's no longer personal, no longer you trying to cajole him out the door but rather the chart just stating a fact. And then you could still keep the unschooliness for the specific activities within each category.
Obviously easier said than done (as with everything in parenting) but IME, when I can blame things on "Well, that's just the rules and Mommy can't help that" then things can sometimes go more smoothly with less argument.
And I do commisserate with you!
I hope things get easier for you very soon.
