Ben
Check the itinerary of the Festival for details of your fun week. I liked the whole package they offer, for a first visit. The also offer a spouse package that is not identical, but sufficently similar. (Dont chose this option, if you are uncomfortable with riding a large A/C bus past hordes of people trying to hop on the back of a tractor to get home from work...Just sayin')
During the Festival, accommodations range from the 6th floor @ Hotel Nacional(one of the few reliable wi-fi hot spots in Havana) to a rented house/apt, legal/illegal, in the city. If you do favor renting a house, consider Miramar, a taxi ride from the patio at Hotel Nacional(ground zero for socializing during the Festival), but not far from many other Havana cigar highlights, leticia @ el aljibe, and lcdh 5th ave, and of course they LCDH Melia Habana. It is also the location of some of the better gastronomical options in Havana, such as Dr. Cafe.
I also like to recomend Nuevo Vedado, if searching for a rental. The prices are most reasonable. This area with many diplomatic residences is warm and charming, and it has a great restaurant tucked on a side street, La Casa. It is where you will find the real machers congregating over dinner. It is a classic, not to be missed.
So much to see and do, so many different possible approaches, art, rum, baseball, techno-salsa. Im sure your GF will be able to find something of interest.
Have a great trip. Buena Suerte.
Drew P