all summer = 93 days (June 1-August 31)
spring break = 9 days (1 school week w/ weekends on either side)
winter/xmas break = 11 days (Dec. 23 to Jan. 1)
EOW friday to Sunday = 52 days
Other 3 day weekends:
Labor Day, Memorial Day, Easter, Thanksgiving, and Veterans Day = 15 days
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Total days = 180 (w/in 5 days of exactly 50%)
If I were Sally, I would check the school schedule where they are considering relocating.. work out a 50% proposal based on that schedule. Assume sally and her dh will do all the driving. The NCP will lose the mid week overnight, but will still have 50/50.
It is very doable. And the kids get the most amount of time w/ both parents with the most effective travel schedule.. meaning they aren't wasting a 3 hour round trip for a 1 night stay. Every trip to the ncp's is multiple days.