We were there last Feb. and rode the chair lift to the beach. I can't remember the cost, not a lot though. There's a kiosk where you can purchase the tickets --or you can walk to the beach on a nice, new paved walkway. The best I remember riding or walking it's at best only a few hundred yards.
The chair lift was fun in itself to ride. There wasn't any lines--in fact we just walked up, bought our ticket and went right on.
I wouldn't worry about buying the tickets in advance, as lots of people just walk over to the beach.
When you get off the ship, you will have to walk a couple hundred yards slightly up hill to get to the shopping area they built--look to your right when you approach the shopping area and you will see where the chair lift starts. The kiosk is right there.