I have children that are not yet school aged at home. Working from home only happens after bedtime (and that's if I decide not to spend any time with my wife after the kid's bedtime).
I also work in an "open" plan (recently transitioned to it). The most productive I ever am is when I'm travelling for work. It's the only time I get privacy.
As a side anecdote: I was listening to NPR about a prisoner that was talking about how he turned his life around in prison and read an incredible amount of books. I was feeling jealous of him for a few minutes until I realized how screwed up it was. I was jealous of the free time and relative privacy that a prisoner had. I never get privacy unless I'm travelling for work. Never.
Perhaps this isn't optimal for every employee/company, but it's how I made the best of the situation for myself at this company...