For all intents and purposes, they are two ends of the same resort, connected by a walkway/boat dock in between. So walking from Swan to Dolphin is maybe 300 yards, closer to each other than many outer builds are at WDW resorts like the Poly and CR and most of the moderates. The used to be served by different hotel chains, but now (IIRC) are both Marriott. The Swan Reserve is a little further away and across the street.