I have started to dream up a big adventure overland tour. Do you know if it is possible?

STAGE 1 - Dec 2008 - 2 months(ish)
Train from HK to Hanoi. Travel down East coast of VIETNAM, up the Mekong into CAMBODIA to Tonle Sap and Siem Reap then continue up the Menkong through LAOS to Vientiane then up to Luang Prabang. Across to THAILAND - Chiang Mai and then travel south through Thailand to Bangkok. Then proably fly back to HK.

STAGE 2 - Feb 09 - 2 weeks(ish)
Hong Kong to Beijing overland. I haven't really researched this bit yet but would like to ge to see some of China on my way North.

STAGE 3 - Feb/March 09 - 1 month(ish)
Beijing to St Petersburgh. Trans Siberian Railway.

STAGE 4 - April 09 - 1 or 2 months (ish)
St Petersburgh to London. Overland through Poland, Germany, Holland, France... I have some company for this bit but the more the merrier.

STAGE 5 - Juy/Aug 09
UK to US by boat (tall ship maybe). Haven't even begun to look a this.

Any help, ideas, experiences would be greatly appreciated.

Jade