Computer programming: have you looked at Alice? It's a free computer programming tool/intro from Carnegie-Mellon, and it's very well-supported so that anyone can use it.
http://www.alice.org/Just a thought...
Making HSing work with your work schedule: one of the nice things about homeschooling is that you can sort of fit it in when it works for you. There are single parents who have school only evenings and weekends. Or can you paint while your child is present? Reading to you or doing something (mostly) silently? An independent child would help a lot there. If that's not your child's style, it could be harder to manage.
Childcare is often the biggest problem with this sort of arrangement. What can you do with your son during the day while you teach? If you have a relative who could help you for free, that's obviously ideal. Balance your schedule with your husband's so that your son is always with one of you? Can your son come with you to the art center or on your DH's photo shoots? Maybe you can trade childcare with another person in need? If those don't work, then you're paying for childcare. And that is not a cheap proposition.
Please know that a "regular schedule" is not a requirement for homeschooling. Some places do require a specific number of hours of work, so you'd have to check the regulations in your state. But they don't tell you when the child has to do the work. It is entirely possible to fit school in around your family's work needs. It's usually harder to do, I suspect, but it all comes down to what works for your family.
Don't worry about the curriculum questions--that's the easy stuff! I promise!
Deal with that stuff later if you decide HSing is even do-able.
No, for you, I think the real question is the schedule and whether it's worth the hassle of working all day and then coming home in the evening to teach your child, or spending most of the weekend on school stuff. It may not be worth it. Only you can decide that. But it can be done without your having to quit painting, depending upon your child's ability to work independently and the amount of support you get from your husband.
I don't know if that helps. I'm happy to answer questions or to talk about it with you more if I can help you to decide one way or the other. I know it's a huge decision!