As others have already said, pack some snackfood, especially if like me you are always hungry! Although food at breakfast, lunch and dinner is always plentyful there are some days when the time between one of these meals is quite long. Cuban public toilets tend not to have any toiletpaper, so do take some with you, although you should be able to collect some from your hotel room as well. Hotel rooms don't have basin plugs so if you want to wash your essentials, bring one of these.
Oh, and if you have a free night in Baracoa and you fancy dinner in a small local restaurant, visit La Roca on 1ro de Abril (by the beach). It can seat up to 12 people and the food is good, the owners lovely and the entertainment very special.
The many guidebooks warn you about the lack of good food, but although the type food on offer was much the same in most places, I thought the quality was always good. The choices tend to be chicken, pork, beef, prawns and sometimes lobster, but always with rice, beans and salad.
You do spend quite a bit of time on a bus, but this is really the only way to see the whole country in two weeks and you get to see lots of the scenery. There are regular stops for toilets and coffee and the bus we had was very comfortable so it really wasn't that bad, especially if you're in a chatty group like we were! Our driver, Ernesto, was one of the best and safest drivers I have come across.
And finally, embrace the culture of history, music, dance and cocktails and have a great time!