My sis & neice stayed at Dolphin in July while rest of our family were at BWV and they it despite the fact that they could not use Magical Express. ( most important to them was being able to attend Extra Magic Hours which you can do when staying at Dolphin / Swan )
We picked them up at airport when they arrived and they took a cab back when leaving (think fare was around $50-$60 not including tip). My sister didn't realize until after the fact that there is a car rental location at Dolphin ( think National ) so maybe renting a car on departure day and dropping off at airport location may have saved money over cab fare. And since their flight was 9:30 in evening they could have had a car to get around more quickly that day for shopping at DTD, last minute park visit etc. There are also other car rental locations on WDW property that have airport locations as well that may make a one way rental worth looking into.