We always have a car so I cannot say. Ideally, Universal could do the luggage transfer for you but they were not doing that at one point. See this link where some say 'yes' and others say 'no' (seems to be a function of staffing and how busy they are):
https://www.disboards.com/threads/will-universal-resorts-transfer-our-luggage.3861580/
The Royal Pacific is almost always the least expensive Universal Premier, so I suggest staying there. (It also puts you closest to Cabana Bay.)
You might have to leave your luggage with bell services and then pick it up the second evening.
Then walk back to CityWalk with your luggage to get a bus, perhaps a 15-minute walk with luggage. (Half that time to get to CityWalk and half that time to get to the bus.). Then you wait for a bus (maybe 5 minutes) and then the bus ride itself (another 5 minutes.)
Uberring will be the physically easiest. I checked prices. At the moment, an Uber minivan from the Royal Pacific to Cabana Bay is about $10.
You can walk directly from the Royal Pacific to Cabana Bay in less time but I strongly suggest you map out the exact route ahead of time. The below highlights in yellow the walk using the street (maybe 15 minutes) but I think there's a way (following the red line) that begins at the path behind the Royal Pacific pool and then cuts through Sapphire Falls that is more direct.
Some of the hotel layouts are confusing. (The first time we stayed at the Royal Pacific, it took us a while to figure out how to get to the hotel's pool.)
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