I did think about the luggage. This trip, we'll each be taking only what will fit in a carryon bag plus just one checked bag for all of us. So if we need to ride from and to the airport with backpacks on laps, it's okay. Once we unload at our pool home, we won't have to worry about the luggage in the van until we go back to the airport.
With a washer and dryer at the home, we'll only need about 3 changes of clothing each. Two of my sons spent 16 days in Europe in May and only carried a backpack. If they can do it to Europe, we can do it to Disney!
You are correct that if we still had small ones needing strollers, this wouldn't be doable.
Two vehicles is our next option. Since DH and I are the only drivers, I'd have to drive all the time and I'd rather not (I would rather look out the window!) plus it doubles our parking expenses. For this trip, that expense alone adds another $186.