You could pick up an Epson or similar card reader / storage unit, but a used cheap borrowed or eBay laptop to simply act as a conduit to a backup drive might be a best bet. Something small, simple, older and easily re-sold on return. Also if lose it or breaks it's no loss. You maybe could use an iPad with right software and connection but larger files from say a MFDB would blow through storage quickly.
On Cuba. I'm CDN, but the country is gorgeous and the people very friendly. Just relax, have fun and bring older t-shirts, ball caps, etc., some spare new toiletries and leave with a note on bed for maid when leaving. With embargo (even if just lifting) the items are hard and costly to get for most workers and US$ too big a PITA to work with for them.
Oh, don't buy cigars or rum from anywhere but proper gov't-regulated store. Risks aside (beach vendors), the gov't is very touch about counterfeit items heading outside the country and they will (or at least did) check cigar boxes at airport departure for the proper stamps.
Have fun - and good plan.