There's at least a few journals on Crazy Guy on a Bike for Cuba.
Also, recently the couple who run the travelling two website did a trip to Cuba, I think with their little kids in a trailer behind them. Reading up a few months ago about it, it sounded like a fantastic place to tour. Sounds like accomodation is pretty easy to come by, as is food and water on the road. Lots of homestay/B&B-type accomodation with families.
Can't remember any mention of being able to hire a bike there. However, if you pack light (eg just a saddlebag of spare clothes and tools and snacks, staying in accomodation), and take your own road bike, its highly likely you'll be well under your airlines check in baggage limit and so I would just take my own bike. Fit some fatter rubber (28 or 32mm if possible) to smooth out the rougher roads, and pack a spare tyre, boot and tubes, especially if you run 700C, I doubt you'd find many replacements of that there.
I'm looking forward to the trip report