We went to Gulf Shores for a few days before and after a cruise the year of the oil spill and we wanted a pool, so we stayed at Island Retreat. The sites were smaller than the state park, but it was quiet at night and had a pool, which our daughters used a couple of times a day.
I think if you call the state park, they have some sites that are "first come, first served" and they are not reservable.
Have something available "IF" you can't get a site at the state park.
That would be our suggestion for spring break - we have done it several times and we have been able to swim at least one or two days during each trip. It's not hot, but it is usually in the mid-high 70s for at least a day or two. On other days, it was in the 60s and not quite warm enough for swimming.