Yes, there is parking available (both underground and surface parking). Guests are cetainly welcome to bring their own chairs and umbrellas. There is a snack bar at the Beach House and another one about 200 yards to the north along the beach - just past the Marriott.
The resort facility, while using private access via room keys, also serves as a public access to the beach - so parking can be a bit scarce at some times of the year. There is a nice bike trail to the beach, the shuttle runs back and forth throughout the day and the resort parking pass will also provide access to the facility at the guard shack.
Enjoy!