Just finished my 8 Day Tour of Cuba, and I can’t say enough good things. This tour operator takes great care of you, the itinerary is very good, and you get to see a lot of the country in a short time. My guide Yasiel was AMAZING, and you should request him, if you can.
If you want to see Cuba 'as it is' rather than through a windscreen, cycling is the only way to do it! Each day takes you to a different location to find and experience different aspects of life in Cuba. The cycling side of things isn't too onerous if you are a regular cyclist, averaging 40 to 50 miles a day at most. There were a couple of 'hilly' days, where the total climb was in the region of 2500 to 3000 feet, but most days the rides were fairly flat. A little hill climbing practice may be a good idea if your biggest hill is normally a railway bridge!
Cuba has to be up there with probably one of the most amazing destinations I have had a chance to visit. I loved the culture, food, sights and the weather.