Hello,Ms.Gian
Fortress Hill MTR station lies at King's Road Fortress Hill, so you can use MTR basicly.

To Disneyland
Island Line from Fortress Hill to Central and then Tung Chung Line to Sunny Bay, and at last Disney Resort Line from Sunny Bay to Disneyland

To Ocean Park
Island Line from Fortress Hill to Admiralty. Then Special Bus Line 629 bounding for Ocean Park

To Noah's Ark
Island Line from Fortress Hill to Central and then Ferry to Park Island Pier 2

To peak and then big buddah
Island Line to Central and then walk to Garden Road where Peak Terminus is there to take you up. Get down to Central after you finish peak tour. Take Tung Chung Line from Central to Tung Chung and then use cable car or bus to get up to see Big Buddah.

Good luck!

Tnx so much Ms.Lily.

Can we take a bus to the following directions?

Hello,again. Ms.Gian
MTR is the most convenient mode of transport in HK. It covers the major area of hk. I would use mtr if i were you.