I understand that 2 million people were transported. What were the logistics involved? How long did it take? Were they under regular attack by the Communists during the relocation?
The decision to move to Taiwan had always been Chiang Kai Shek's back up plan. Ever since 1949 when the war really turned against the Nationalists he had been making plans to move the government to Taiwan. The reason he choose Taiwan was that it was easy to defend because the Nationalists still maintained air and naval superiority. He knew he wouldn't be able to take back the mainland himself; Shek's plan was to bide his time on the island until the inveitable (as he saw it) war bewteen the USA and the USSR broke out, naturally the communists in China would support the USSR and the USA would be forced to help Chiang Kai Shek get China back. Chiang didn't leave for Taiwan until December 10th, 1949 when the situation on the mainland completely fell apart.
The evacuation was relatively easy as the Nationalists had complete domination of the skies and the sea, the communists had very little in terms of aircraft or navy so they couldn't do much. The evacuation was also aided by a successful rearguard action fought by General Hu, there was also several other pockets of resistance that held out against the Communists.
Source:
A History of China by Jonathan Fenby