The component that's making it so expensive is flying home on December 17. It's too close to Christmas.
Apparently, not close enough for SW to have a later direct flight than 6:50 PM. Last November our flight left at 9:50 PM which gave us a long last day and I loved it! I was hoping for the same this year but no such luck

Sept 10-20th

Our original dates are 10-17th, and the kids would miss 5 days. With the new dates, they would miss 7. We would arrive back home on a Tuesday afternoon, and they would go to school on Wednesday morning. I have both reservations just in case, but I need to make a decision by tonight to catch Southwest's sale.
Too bad I can't change my dates. That's great for those going in September!
After planning this trip for years, it's now coming up really quickly all of a sudden!!!