We've gotten hooked on splitting, because we get to choose two resorts instead of one! I always have a hard time choosing, so this is a huge plus for me!
Sometimes, we split just to be closer to MK/MGM area. Other times, it's so that we can save money (lower-priced resort/higher-priced resort). I've never found that the moving day is any more difficult than a non-park day. We usually pack our dirty clothes as we go, so that isn't an issue. Sometimes we head to a park for early entry that day and sometimes sleep in. I pack our non-essentials the night before we switch, making sure there is a small bag with swimsuits, etc. The next morning, I pack our nightclothes and the toiletries, check out and take a taxi to our new resort. This lets us have access to our luggage for the whole day, and we've never paid more than $13 + tip for the ride. Well worth it for the convenience, IMO. (We are usually a party of 2-3, if you have a large party & need a van, that would be a little more.)
When we get to our new resort, if there is a room ready, that's great! If not, we continue with our plans for the day, whether it be hanging at the resort for a nice lunch and a swim, or heading off to one of the parks. Just as we would do on our original check-in day. If we are checking into a resort that we've never stayed at before, this gives us time to really explore. My kids are now teens, though, so it's probably easier for us to go with the flow - no afternoon nap is more of an inconvenience for me than the kids, lol!
I do agree with the posters who say that 3 days at each resort is the minimum for a relaxing stay. We've done a 2/2 split, and we didn't get to enjoy either resort as much as we would have liked.
HTH!
