We had the same deal you do for $369/night.
Plus, Marriott called the day after our arrival and offered our last night free if we would do their TS presentation. We'd been through it before but did it again. I think it lasted 10 minutes. Not much to tour since we were already staying in one (!)
I'm not sure of the surf place name--Island Adventures or something. But you can't miss them. They're right on the beach--a little farther down past the Kaanapali Ali.
Surfboards lined up on the sand. If you do take a lesson, they loan you UV short sleeved shirts. But bring your own LONG sleeved one (buy at Costco). It'll save your arms--everyone had rashes afterwards (friction from the board and salt water).
Have a fabulous time. If you have any more questions, just ask.