The OP is staying at CBR, which has multiple bus stops. Once the MK bus arrives and you board, you may have another 10-15 minutes of them circling the remaining (potentially) 6 bus stops, loading/unloading
ECVs, etc. They would then have to walk from the MK bus stop to the boat, wait for the boat and hope there's no line where they can fit on the next one, and boat to FW. Even if OP had to wait for the internal bus at FW and go through the stops there, I would still say Ubering there and dealing with that would be faster. The difference might not be significant, so it would really be up to OP to decide which they'd rather hassle with.