I am planning to reach Gangtok via the silk route starting from Lingtam. from Gangtok i would like to visit Gurudongmar lake and Yungtham valley. Is the total tour possible within 6-7 days including a day at Gangtok for sightseeing? I am planning to go around February 15th. Is there any option for white water rafting in Gangtok at that time? Can anyone make an itinerary for my trip?