Darjeeling to Namchi is 2 hours 7 minutes and from namchi to ravangla is approx an hour. So you can stay in Darjeeling for two and visit the Tiger Hill, Tea estate,Singalila National Park and many more sites in three days. After here you can go to Namchi Solophok Chardam then other Monasteries .Ravangla Buddha Park and many other monasteries in the last leg of your trip which can be covered in a day.
Hi Jitu, It's heart warming to know that you are looking to explore Darjeeling and it's surrounding in about a week's time. However, I really feel that a week is too long to explore only Darjeeling and it's surrounding. Only a fortnight back my friends and I explored entire North Bengal and also touched upon bordering areas of Bhutan, Sikkim and Assam and all these in just 8 days.
If you believe you have about 7 days to explore Darjeeling and it's surrounding, you can message me directly on Tripoto and i can share my itinerary with you. regards,
Sudip