As a DLR vet, there are multiple things to consider. Here are my two cents:
o Taking hotel breaks can take a long time - be careful with this
On our trip last month it took us 90 minutes to get from MK FantasyLand to our hotel room at the Swan by Disney bus. To be fair, we did make a quick stop on Main Street at a store on the way out. So call it 75 minutes. I am not saying this is typical but I am saying that taking breaks can take a lot of time out of your day getting back and forth to your hotel.
o The ease of taking hotel breaks depends a bit on which hotel you are staying at.
For the days we were at the Swan, Epcot and DHS were much closer and easier to take breaks from
When we were at AKL, the same was true for AK park
o DHS is under huge construction right now with limited attractions and shows available. You can finish by 3 or 4PM if you want and make that be a half day
o AK used to be considered a half day park by many, but with the new Rivers of Light show at night and the opening of Pandora on May 27, that will change
o Make some dining reservations - WDW has many cool dining options - but lunch may be a better option than dinner if you want to take afternoon hotel breaks. The reason being is that you know you will be at the park at lunch but dinner timing is uncertain because of the potential hotel break
o Plan 2 days for MK and 2 days for Epcot
o As for breaks at the parks, Epcot has so many places you can just park yourself for awhile. Especially in World Showcase. For the other parks, not so much unless you are dining somewhere. AK has 2 animal viewing trails which are worth doing and sort of like a break. Not too many benches there as I recall and a mix of shade and sun.