How to collect train ticket (a US citizen)

I booked ticket to Beijing on 11/7/2013 and I plan to travel on bullet train from Beijing West to Guangzhou South on 11/16/2013. I am told to purchase ticket 20 days ahead of times. Although I am going to make reservation for hotel in Beijing, I wonder if I should use my hotel address or my Chinese friend's address. What will be the best solution? Moreover, I plan to purchase tickets from Guangzhou South to Shenzhen and then Hong Kong (New Territories). Any suggestion for both questions? Greatly appreciated for any suggestion. Best. Chhan