Is there any homeschooling group or co-op around? Remember, homeschooling does not have to mean that "there are no other kids around." In our area, we could be with kids every single day of the week, easily!
We have DS7 in a sort of school for homeschoolers this year, so he's even in classes with kids once a week, plus he's in enrichment classes for GT kids another day of the week. Price for something like that might be an issue for you, but it's worth looking into. If you find something along those lines, it's possible you could offer to teach an art class or two in exchange for his fees.
If there is nothing like those but there is an active homeschooling community, you might consider starting something. That's what most homeschoolers do if we feel the need for more organized time for our kids to be with other kids: we just plan it! Create a game day, a Lego group, a park day, a math club--or whatever appeals to your particular child--that meets once or even twice a week.
Homeschooling does not have to mean being alone. Honest. See what's around before you decide that loneliness is your only option. You may be surprised.