To Whom it may Concern

Could you please give me information on what train service travels to Dongguan.
What is the distance from Hong Kong and how long does it take?
Do I need a visitors visa?
Is the tea garden in the city or out of the city and how far? I would also like to visit the Opium War museum so where is it.
lastly is it quicker to go by boat from Hong Kong?
Thanks again. Warren Cardwell