If over night in SJU, perhaps check with airline (puddle jumper) and see if any seats available on the early morning flight (ie 7:00) and if so, how accommodating ($) they can be to moving up. This could allow you to get to TMM by 9-9:30. Have provisioning from Riteway arriving that morning or depending on your needs, you can provision from the small Riteway located next to TMM. We take a cooler of frozen/vac-sealed meats so that helps.
Upon arrival, place personal bags in cabins (can unpack later). Inventory provisions if present or send shoppers (Only part of crew to small Riteway) while Capt/Firstmate begin check out with TMM Staff.

I think very reasonable to get off by 2pm-3pm, assuming you arrive TMM by noon, but need to have a game plan with delegation of duties. And be mission oriented.