If i had a lot of sand that nothing grew in I would build a chicken tractor and move it around as needed. Between the droppings the bedding and the chickens scratching that soil will get fertile. Tilling oak leaves in will help you get good organic matter in your ground too. That sand with enough organic matter can be an excellent sandy loam. If you drink lots of coffee do not waste those grounds. They are full of nitrogen and can be applied directly to your gardens.
Be careful of designing raised beds on sandy soil. Any raised bed needs a good bit more water than a regular bed, and on sandy soil you nay have trouble keeping things from drying and wilting even if you have no practical or ethical problems with a good daily soak.
In terms of what veggies you can grow, heck, you are in a state that specialized in excellent market garden produce... there is not much you can't grow! Well dunno about watercress I am duly jealous. Make some giant tomatoes and great melons for me, k?
Pat, who grew up outside of Philly, lived in NJ for a while, and considered boarding my horse at a barn near Jackson