Is trian the best way to go from Guangzhou to HongKong for family with kids?

Yes! Travelling by train is a nice choice for you. Upon arrival at Baiyun Airport, take metro line 3 from the airport to East Railway Station. The metro ride takes about 30 minutes, and the fare is CNY 7 per person. Then, take a train to Hong Kong (about 2 hours). You can pre-book the train tickets through bookingtravelchinaguide.com.

After arriving at Hung Hom Railway Station, you may take MTR West Rail Line from Hung Hom to Nam Cheong Station, and switch to MTR Tung Chung Line to Sunny Bay Station. Then, change to MTR Disneyland Resort Line to it. The MTR ride takes about 35 minutes, and the fare totals HKD 23.6.

Or, you can take shuttle bus line 5 from Baiyun Airport to Haizhu Square (about 1 hour). Then, take a direct bus to Disneyland Resort from the nearby GZ Hotel (about 3 hours).

As for accommodation, the Disney's Hollywood Hotel inside the resort is recommended to you. It provides clean environment and nice service. You can book a room by dialing +852 3510-5000.