Hi, Lijiang is a beautiful place. 2 days are enough to visit the three places. The Tiger Leapking Gorge is on the way to Zhongdian. But i think Dec is a little cold there.

Ms.Ta,

For Lijiang area, if you are interested in visit snow mountain, Black Dragon Pool and Gorge, also Shangri-La, you can do like this:
Day1 Lijiang---Jade Dragon Snow Mountain---Black Dragon---Lijiang stay in guesthouse in old town
Day2 Lijiang---Tiger Leaping Gorge---Shangri-La stay in Shangri-La
Day3 one day trip around Shangri-La to visit Putacuo National Park and local Tibetan village, old town stay in Shangri-La
Day4 Shangri-La---Lijiang
in the morning visit Songzan Lin temple, then driving about 3~4hours back to Lijiang. then catch up the train or sleep bus.

For the trip in Lijiang and Shangri-La area depend on how much time you do have, otherwise there are many nice places to visit to. Hope this is helpful for you!

During Dec. Shangri-La is kind of colder than other places.