I will be going to Shangrila by bus in early April 2014 from Kunming, can please some one tell, is it necessary to pre book the bus tickets?

Generally, no need to prebook the bus tickets. If you wish to, you can surely ask your hotel to book that for you; however, I heard the tickets prebooking is only available one to three days ahead before the departure date. You may weigh the need to do that.

Thank you very much indeed for your reply, very useful.

I further want to ask is there any sit in coach tour from Lijiang to the TLG , the snow mountain and the white water terrace.

thanks

From LJ Bus Station, you can find direct buses for TLG and the buses are frequent.
From Hongtaiyang Square (Red Sun Square), you can find the direct buses line 7 to the snow mountain.
To the Whitel Water Terrace, there is one direct bus from LJ Bus Station and it is at aroun 08:30.

Thank you for your reply! It's great.