Thats about it for us too. I try and start around 9 and finish between 12.30 and 1pm. As the weather is starting to cool down now, I found that this past week we started around 10 and finished around 1.30pm Anywhere from 3 - 4 hours is a normal day for us.
It varies but we like to try to keep it around 8:30. Ds 12 goes running with me, so some days we do it in the morning if we know our evening will be busy. On days when they have activities in the afternoon, I am more strict about starting early.
I agree. When we're home, we start anywhere between 7:30 and 9, and go until we're finished. But, we break for snacks, a little physical activity (bike riding, maybe), and lunch, if needed. When we're out of town, we have breakfast, then generally I impose a "You have to finish these specific tasks before we leave the hotel room!" statement. (I found if I didn't, I would ahve to pull teeth to get things finished.) The exception is when we have a field trip planned.
We start after lunch usually, and it takes us 2-3 hours. My DS is only in first grade, though, so I know we'll have longer days as he gets older. I am not at all a morning person, and we usually run our errands before lunch, so this works for us. I think you just do it when/how it works for you... the beauty of homeschooling. : )