OP, go to
www.allearsnet.com and check out the menus for the restaurants. You should be able to figure out where you want to eat and what your family is
most likely to order. That can help you decide if you want to pay cash or choose the dining plan.
One suggestion would be to make a reservation for mid-afternoon, and just have a snack, i.e Sci-Fi Dine In at MGM. You could book for 2:30-3:30 and just have milkshakes and fries/onion rings or an ice cream sundae. It would give you the opportunity to sit down in air-conditioned comfort for a little break mid-day without having the expense of a full service meal. The Sunshine Grill at Epcot is all counter service, but has several options to choose from and all inside in airconditioning. There are lots of great options for having a cooling break (which you will need in July!)
I would consider parkhoppers because it will be very hot and crowded (Animal Kingdom will be the worst!) and you might want to have a little break in the afternoon and go to a less crowded park. Lots of people recommend one of the following strategies:
1) Either take advantage of the park with the extra magic hour in the morning, get there early when it is cooler and then head to a different park when the crowds get really bad (around 11:00 - 12:00.) OR
2) Avoid the park with early entry, and instead, go to the park that had Extra Magic Hours the night before. For example, if MK had extra magic hours on Monday night, then go to MK on Tuesday at park opening. The folks who were there late the night before will either be sleeping, or enjoying whichever park that has the extra hour on Tuesday mornigng.
In any event, I think that since you only have 4 full park days and it is your first visit, you will want the flexibility of being able to "cut and run" if a particular park is too hot and crowded for you to enjoy.
I am certain that I will be in the minority here, but I would also suggest that since you will have your own vehicle, you drive yourselves to the parks (parking is free for onsite guests anyway). If you are hot, tired and cranky you will want to get to the airconditioned comfort of your own vehicle and get on your way quickly, instead of waiting in the heat for a bus, and probably having to stand anyway. If you or hubby need or want to leave with one of the kids (illness, fatigue, meltdown, whatever) you could still split up easily and use the busses/monorail then.