I've done a 3-resort split trip (see my signature), but it was not over only 3 days. I'd only even think of doing a 3-day, 3-resort trip as part of a resort-only trip, where we were spending the full day enjoying the amenities of each resort, with plenty of time to relax so that the moves don't feel overwhelming. And if I did that as a resort-only trip, I'd hand carry our luggage from resort to resort, ask for late (12pm) check out at each resort, & spend the mid-day doing lunch, pool and other resort/non-park activities. But for a short, parks-focused trip, I'd only do it if there was no other way.