We had a similar issue during our last trip (this past February.) There are a couple of options:
1. In the later afternoon, there is a shuttle you can use to travel between CBBR and the other resorts. It is primarily there to allow folks to eat at the other hotel's restaurants.) But you would have to get the concierge to hold your luggage until later in the afternoon when you would come back to CBBR, pick up your luggage and then wait for the afternoon shuttle to come (on a 30 minute schedule if I remember correctly.)
2. Take the shuttle to City Walk and then take another shuttle to other on-site hotel you are staying at. The other hotels do have shuttles that come/go in the same area as the ones you use for CBBR, but I don't think the other hotel shuttles run nearly as often as the CBBR ones (so you might have to wait up to 30 minutes or so.)
3. Take the shuttle to City Walk, then go through security, walk to the water taxis and take a water taxi to the new hotel. If you have a lot of luggage with really big bags, might not be all that easy to do.
4. Take your luggage and walk to RPR. If your luggage has wheels, there is a walkway you can use. If I remember correctly it took us about 15-20 minutes to walk from CBBR to RPR. And while we weren't in a hurry (i.e we could have made it more quickly), we also didn't have a bunch of luggage slowing us down either.
5. Uber/Taxi - while this option does have a cost, it is probably the easiest/quickest way.
