St A's is an amazing place. Been ridding there sense 98, Son of sand is right on all accounts. How ever, Memorial weekend is still to early in my oppinion. Been there many times on that weekend and have been rained out and snowed on. If its your first trip I would wait till later on in the year. If your looking for a big week end with lots of people, I would go on the 4th of July. Of course rain, cold, or snow, your still at the dunes so life is good.