You can take Subway Tswen Wan Line to Lai King and change to Subway Tung Chung Line, Ngong Ping 360 Cable Car station is not far from The MTR Tung Chung Station, subway fare would be HKD12.5.
Citygate outlets is also not far from the MTR Tung CHung Station. You can take SUbway Line Tung Chung and change to Disney Resort Line at Sunny Bay Station, it also costs HKD12.5. I think one day is enough for at most 2 places, you can visit Ngong ping and Citygate in one day and Disneyland in the other day.

Thanks for your advice. But if we only visit Ngong Ping 360 to get experience back and forth by cable car,particularly crystal cabin, and not go ( step up ) to Giant Budha , is it still possible to cover it with City Gate then HK Disneyland in one day because I don't know about time estimation on each place.For example after breakfast go to Ngong Ping 360 back and forth, go to Citygate and spend 2 hours there and visit HK Disneyland from afternoon until night ? Thank you.

In that way the time would be enough, I think.