Stay in Gangtok and there is a process to file an application to climb further over to Tsongmo lake. You will need to book a local SUV. If you go through travel agents including stay in Gangtok, they will take care of the application which is verified by our Army post. Sikkim rum is very famous in the country so enjoy your drink there. Avoid drink when climbing up to Tsongmo. May is the best season to visit if you wanted to go up 14K feet than just stay in Gangtok and enjoy your rum ;-) Hope that helps.
