You can get to Victoria Peak and Avenue of Stars in the first day. From Mongkok to Disneyland, you can take MTR to Lai King First and then transfer to Tung Chung Line to Sunny Bay. There is the special Disney MTR line to Disneyland (totally 18.5HKD). Day 3, take MTR from Mongkok to Admiralty(10.5HKD). OUt from Exit B to take bus 629 (10.6HKD) directly to Ocean Park. In Day 4, the dolphin watching means go boating in Tai O?! Remember the day to Disneyland that getting off at Sunny Bay on Tung Chung Line. This day, get off at the next stop after Sunny Bay - Tung Chung Station(15.5HKD). Get out from ExitB and walk 5 minutes to the Ngong Ping 360 Cable Car Station. Take the cable car (74HKD for single trip) to Ngong Ping Bazaar to see the Buddha. Lantau Bus 21 (6.6HKD) can take you from Ngong Ping to Tai O. Last Day, take airport bus A21 (33HKD) back to HKIA. The price I give is the fare per person without discount. Children 3-11years old pay half the price. If you buy Octopus card，the price is cheaper.