alot depends on how much time you have for your vacation....
getting to the parks early is the single most important thing at disney...if you're at the gate at least 30 min before the official park opening time, then you will be able to see most of the rides that you want before it gets to busy...then you can head back to the hotel for some rest...which in the summer is a must, esp if you have kids...you can go back to the park in the early evening to see shows/parades etc...
if the afternoon parades are important, you can sleep in one morning and then go in the early afternoon...see the parades and then stay and see the fireworks etc...
the important thing is to have a plan....decide with your family what rides will be a priority...those are the things you're going to want to see when the park first opens before the lines get too long...
however, going at park closing isn't bad either...we went to AK last weekend at 4pm...the park closed at 6pm...we saw the afternoon parade, kilamnjaro safaris, dinosaur and it's tough to be a bug in less than 2 hours...
as far as exact times...it will vary daily...depending on what time each park you want to go to opens and closes...when and what you want to eat for your meals...you can eat a light b-fast and then when you take an afternoon break eat a large lunch...or a large bfast, light lunch and then dinner after the parks close at a hotel restaurant....also, alot depends on which hotel you're staying at...the possiblities are endless, but depend on what your family likes to do...
we are early risers, but also stay up late...many times start our day at 6a or 7a and end up on the Boardwalk at night till midnight or later...so for us an afternoon napbreak is a must...
and remember...it will be hot!!!!!!!!!!!!!!
we just went last weekend and we are also going again in august...(8/25-9/1)...the afternoon heat is brutal in FL...