You could probably get away with decent crowd levels the very beginning of March, but March as a whole tends to be rather busy with spring break crowds heading down.
As far as weather goes you'd most likely see days in the 60s - 80s so I'd pack a variety of clothing. Jeans are always one of my go-tos when visiting that time of year because mornings and evenings will be COLD and then during the day they can be rolled into capris when it gets warmer.