ah...the dilemma....yup. You just gotta start booking some of those ADR's without knowing the full schedule. But don't worry, six months is more than enough time to plan...
So you don't stress out too much, they don't always release the schedules six months out. I've seen times when park hours were only released about two months in advance. Some things follow distinct norms form year to year, but they don't realease a full schedule (parade times, resort activities) until about a month in advance.
Usually, regular park hours fall about like this: Epcot is 9-9; Ak is 9-5 or 9-6; MGM is usually 9-7:30, 9-8, 9-10 at the latest. Mk's hours are the most diverse - anywhere from 9-6 to 8 - 4am (with EMH, and maybe even later).
They have also been known to do things like rotate EMH hours periodically, and make last minute revisions. More than once we've gotten to WDW to find out that park (closing) hours were modified by an hour one way or the other. Usually they add park hours if they are going to change them at all, but once they shortened MK's schedule by one hour.
