We have split one of our stays in the past and the process was painless. We called to have our bags picked-up from the room early on the morning of the move. We were given a tag indicating the number of bags. When we checked-in at the second resort later that day our bags were waiting for us. We left some valuables in our bags and at least one camera was left behind. No problem.
On other stays we have left our bags with the resort on the morning of our check-out then gone to the parks until late afternoon before leaving for the airport. We have left a laptop with them and we did not have any problems.
Enjoy your stay. The move will be painless, aside from having to pack-up and then unpack.