Congratulations! The Westin Kaanapali Ocean Resort Villas on Maui is an awesome resort. Even the studios are VERY nice - jacuzzi tub.
http://www.westinkaanapali.com/index.htm
One of the first things I would do is buy a copy of "Maui Revealed." The revealed books are my most favorite Hawaii guidebooks ever! We used our Maui Revealed book to find Lindbergh's grave. It had tips on where to park for free (without getting towed) when we wanted to go to Napili Bay. The revealed books are only about $16.00 and worth every penny. We used it when we drove the Road to Hana, too, to find various waterfall stops.
We snorkeled out in front of the Westin. Black Rock is close by and the sea turtles were all around that area (at least they were a few years ago).
Here's a link to the revealed authors' website. The aerial views of resorts are free to look at. They don't have a picture of the Westin timeshare resort, but they show the Westin hotel. The site also shows the Sheraton at Kaanapali which is sitting right at Black Rock to the right side of where your resort will be (if your trade is for Westin Kaanapali Ocean Resort Villas).
http://www.wizardpub.com/main/home.html
Have fun.