Unfortunately March is not the best time crowd and price wise. You will find the room rates to be higher since it is considered Spring Break season.
One thing to look at is when Easter falls next year. This year it was the earliest it has been in years so that made the end of March a bad time. I think if you plan for as early in March as you can you will be okay. I would shoot for the very first week if you can. You will pay the higher room rates but the crowds should be lower than they will be at the end of the month.