I think you can successfully get a mediator to agree that since your losing EOW that those days should add up, and give you the majority of the summer, in exchange.
She most likely will have a valid argument that your days will be spoken for because of work, and would want to know who D4 will be spending her days with.
You'd probably also get every other major holidays (easter, xmas thru new year, thanksgiving) providing you provide the airfare since your the one moving. You get odd year/she get even years for the major holidays.
You could probably get this on you own. If not, cancel the mediation and appeal, then come back in front of the judge with a lawyer.
I don't envy your situation whatsoever. Your going to be spending the majority of your income on CS, airfare and child supervision in the summer months. The problem with the summer months is you wont get all of it (June, July and August). Most likely you'd get 3 weeks out of each month, then one week with her, increasing your airfare exponetially.
Wont know till you meet up in front of the mediator .
"Wrap it up in latex or she's going to get your paychecks."