Southwest trip summer 2017 - where should I reserve?

Thanks everyone for the input.

Yep, I know we're going into "hot" season. I had the trip planned for earlier in the year but we just couldn't swing it with the kids' schedules. So it is what it is and we'll make do.

It looks like there are reasonable cancellation policies at most of the places so I'm going to grab the spots that I can now and change later if needed. Since we already know our trip dates, we might as well.

Thanks!