Visited Cuba last year for a month. Larger cities like Havana, Santa Clara, Santiago de Cuba have some spots, mainly hotels that offer internet. In my experience it’s your lucky day if you found a hotel with a working WiFi spot. Even most of the 5 star hotels I visited don’t have a working internet connection. And if they have a internet connection, it is usually hooked up to an old Windows PC and quite expensive to use (10 US dollar for an hour, 500 KB/s connection). Your best changes are in the few American run resorts.
So, unless you bring your own illegal satellite connection (yes that was illegal in Cuba when I visited), you should prepare for a lot of time without an internet connection. I simply gave up and went offline almost the whole month.
Make sure to download ForeverMap witch caches OpenStreetMaps maps for offline usage.
Very useful, since most streets don’t have street names and a lot of roads don’t have signs and/or directions. Buy a local map as backup, or for the occasion you want to ask for directions (since GPS was also illegal when I visited Cuba).
I do agree that the Cubans are very helpful and they have a amazing culture. If you’re open for adventure and haven’t been there, then you should definitely visit Cuba at least once in your life. It was one of the most interesting countries I’ve been to.