In our area, the schools go for 36 weeks. I plan 3 twelve week terms of work. While we don't have attendance requirements in FL, I'd be uncomfortable schooling less than the 180 days schools require. I do think the time is reasonable.
The first thing I do is sit down with a calendar and mark off any trips or big vacation day chunks and I plan around those. I start in September and finish in August with our year round schedule.
Typically, I plan 3 weeks of work followed by one week off. We take the off week to do whatever's needed - shoe shopping, dentist appointments, big projects around the house, fun things. However, if we didn't quite finish our 3 weeks worth of work, we do continue schooling albeit at a much lighter pace. I find it's a very good schedule for us. If I have closets that need organizing, but I know it will take a chunk of time, I know I have time for it within the month. That helps me not get so sidetracked.
We take ~ 3 weeks off at Christmas, 2-3 in the spring or fall and 2-3 before the new school year for me to plan. Later, I'll link our calendar for the 2013-2014 year. I find visual examples helpful.
Andream - start with the number of days/weeks you're required or need to school. Work backwards from there, penciling in weeks you wish to be off. You'll be able to see if your goals line up.
Blessings,
Christie