We homeschooled all three of our kids, currently in 8th, 10th, and a freshman in college (full-ride academic scholarship, yay!). We've participated in several homeschool groups in our area as well as 4H, with mixed results. All have been semi-active in church youth activities, in fact we recently moved to a new church that's closer, larger, and more active to give them more opportunities.
Also, check with your local school. We live in an area that's very homeschool-friendly, homeschooled children are considered part of the local school system. My oldest played on varsity sports teams and any homeschool child may participate in any after-school activity or even enroll for single classes as desired. Also check out local community colleges for dual-enrollment options, my oldest completely almost two years worth of university credits where we only had to pay the cost of renting her textbooks (again, yay!). She got credits, acclimated to a university teaching style, and made many friends.
Homeschooling doesn't have to mean schooling at home.