KTPie- look at "A Well Trained Mind" community. It's primarily a homeschooling forum, with an active "after schooling forum."
There is a lot of information about curriculum, challenges, etc. They even have an "accelerated learner" board for kids performing above grade level. Many programs, methods, etc. are discussed.
I don't home school but have considered it. To me, the challenges (might) be:
1. finding a rigorous, comprehensive curriculum
2. dealing with the occasional clash of my personality and DS7's personality
3. appropriate socialization
Honestly, with all of the support that exists for home schoolers, it's really #2 that's our hold out for keeping DS in regular, private school.
A couple of things:
1. I really, really like Singapore math, especially the word problems (they can be quite challenging). I have DS do about 10 minutes of after school math- we use Singapore word problems and I come up with whatever he needs to know on a particular subject. Right now, we're finishing fractions, decimals, etc. and moving to order of operations in prep for algebra.
2. We are going to work on the Art of Problem Solving some this summer because I've heard good things. Many folks seem to like EPGY. Kumon workbooks are tedious but great for math facts.
3. Language arts- if it was me, I would focus on writing. I have family member who are high school teachers. They say the average writing ability of an incoming HS freshman is appalling.