Will be going to Hong Kong in December 21, 2015. Would like to have some travel plan.

Well, here is the route I recommend.
HK – Macau – Zhuhai –Kaiping - Shenzhen
From HK to Macau, you can take a ferry from HK-Macau Ferry terminal or China Ferry Terminal to Macau.
From Macau, take a bus or Taxi to Gongbei Border, passing the border, you will arrive at Zhuahai.
In Shenzhen, you can pass the Luohu border to return to HK.
Right in the Gongbei Bus Station, you can take a bus to Kaiping.
In Kaiping bus station, you can take a bus to Shenzhen.