1. Don't arrive or depart on Saturday or Sunday
2. Get your groceries BEFORE you come on the island, the stores are CRAZY as everyone shops all at once
That's what I remember from the beach rentals we used to do before getting our camper.
We have avoided beaches because of sand in the camper.
Another tip: Baby powder on a cloth and rubbed on you after the beach helps remove sand and the stickiness from the salt water.
Looking forward to reading all the tips about the beach :C