I was educated in a government school, and do not have children, but I think that the social interaction thing, is overblown. I had two friends, in school. The rest of the time, I'd rather spend it by myself or with adults.
With homeschooling, learning could and should be an everyday concept....The only reason for summer vacation is because classroom learning is boooorrrring. I think there are some statistics on how much retention is lost, due to summer vacation.
Teach the basics and let social interaction be part of everday life....A kid doesn't need to visit every art or natural museum, within a hundred miles, to get the gist of it.
Instead of dropping money on social get togethers, spend some money on a couple Rosetta Stone courses, and then, the kid will really be able to interact, in the world, as we are coming to know it.