Hey Saurabh, Yes it is a good time though be careful of some light showers. I have attached with this comment few options. You can click on them to find more details about them. If you want to talk to someone about the packages simply fill in your details in the form and you will receive a call.
Bikes are allowed in Sikkim. Just after monsoon, this is the best time to travel with clear sky and moderate temperature. It gets really chilly at night. It is also a good time for photography.