I’ve stayed at both and prefer the Swan, but only because I had a bad work experiance at the Dolphin. The resort itself was great.
As with all the EPCOT resorts it is a quick walk to the back entrance to EPCOT and the monorail from there takes you to the Magic Kingdom. ( At least that’s the way we do it. )
You will have lots of dinner choices between the Swan Dolphin and the Boardwalk area. This area is actually my favorite resorts to stay at.
Now the down side, the two resorts are not heavily Disney themed, but to the plus the service is every bit as good. And in my experiance the staffs get it.
I think you will have a great time! Sure wish it was me!