We have kids roughly the same age, and we don't get hoppers. Once I am in a park and have the stroller situation settled, I hate having to pack it all up, fold the toddler's stroller, return the rental for the older two, etc. Then, the time wasted to actually switch parks...
We don't take afternoon breaks either. Maybe if you do, you might want to visit a different park in the late afternoon or evening? Personally, I don't think it is worth the added expense unless you will be hopping almost every day.
With a 6 day ticket, I would do 2 days MK (definitely), one day AK, one day MGM, and one day epcot. With the extra day, our family would probably go to epcot again since it is a large park, although, I know many kids don't enjoy epcot (mine do though). You probably want to save the last day to see where your family wants to go back to. You may even want a third day in MK.
Whatever you pick, there is plenty to do!