1. what is airport express, the one like MTR or bus?
2. 4 of us,( 2 adult and 2 8 yrs old) should we buy the express pass or octopus card?
3. which hotel or location we should stay be best to each location,our budget $100-150 per night(room for 2 adults is fine for us, cheaper )

D1 to 360,Mong Kok
D2 to ocean park
D3 to Mong Kok, TSIM SHA TSUI and hong kong island peak and ride the tram.

thank you very much.