I'll be honest that in the years that I've homeschooled I have not incorporated enough social activities. That's not from lack of opportunity but from motivation on my part. Since moving to North Carolina, I became a published author and things got busy and crazy at my house. Is that an excuse--well, sort of. So, this year I decided to rectify that situation.
I signed up for several activities for both of my children. Field trips, park days, skating, bowling, etc...My oldest is taking band. The youngest is in Cub scouts. Then there is church. We had it covered. We were socializing!
The problem was we were socializing too much. By the weekend, I was burned out and I had schoolwork to look over and file. I had new lesson plans to write out and supplies to buy. When did I have time to breathe--let alone write?
Socialization is never a problem when homeschooling. The real problem is picking just a few activities and sticking to it. What I did is give each of my boys one long term activity that takes place weekly and then the occasional activity only one a week or every other week. It's enough to keep them involved without burning out.