You can check as many pieces of luggage as you wish, as long as you are willing to pay for them. My Grandparents go to Florida every year and always check about 7 or 8 bags between them. The first 4 are free and they pay 90.00 one way for each additional suitcase. This is USAirways fees. Other airlines may charge different prices. Nevertheless, don't just assume your airline won't allow it, they will. Its revenue.
Have a GREAT time!!! Gosh, 108 days, that is a dream come true!