When we stayed at Pop Century last summer we had our car with us and just drove to the other resorts for ADRs. We ate at Grand Floridian, Contemporary and Animal Kingdom Lodge. We chose based on the restaurants we wanted to eat in (1900 Park Fare, Chef Mickey's, Boma).
If we didn't have the car, our plans may have been different, or we could have taken a bus to a theme park then transferred to a resort bus. More than likely we would have scheduled meals only in the MK area and taken the monorail after the bus.
The way we tour the parks with the kids is.....we go very early in the morning (we wait to get in before rope drop), get the rides done in the morning, have an early lunch (before noon for sure), do some other attractions, then take a break in the afternoon and go back to the hotel by 2PM for a nap. We get a lot done in the morning before it gets unbearably hot, then go back in the evening if we have an ADR or just go to a resort ADR for dinner. Our kids are small and they handle this schedule very well.
Since we will now be staying at Boardwalk Villas from now on, we have several restaurants to choose from in that area and so we will take advantage of the restaurants at the BW, BC and YC resorts. It is a bit easier to get to other resorts from the Epcot area, since you could either walk ot take the boat to DHS and then take any resort bus you need from that theme park. Once again though, we will have the car with us so we would more than likely drive to Contemporary, Wilderness Lodge, etc.