Inquiry abt the activities in Whitsunday‏

Dear friends,

I'm writing to inquiry abt the activities during my stay at Whitsundays Islands:

1) My husband and I both have YHA cards, on which activities could we enjoy discounts?

2) Our itinerary is from 23032014(Arriving at Airlie Beach around 12:00am)-26032014(leaving for the airport at 14:00 pm that afternoon), my initial plan is here as follows:

Day 1-Get to know Airlie

Day 2-Cruise tour

Day 3-Whiteheavn tour (includ. Inlet Hill)

Day 4-Helicopter tour (half-day)

Sounds resonable in my case or not? And what kind of activities would you guys recommend?

3) Any good agent with good pricing to share?

Pls suggest !!! Thnks!!