Gangtok is built along a steep ridge, and walking between points of interest involves significant climbs. Shared jeeps are the main local transport and run along fixed routes through town — they are cheap and frequent, but you need to know your stops. Taxis can be hired for the day or for specific journeys; agree on a price before you set off.
For day trips to Rumtek or Tsomgo Lake, shared jeeps run in the morning from below MG Road, or you can hire a vehicle with a driver. Most of the central sights — MG Road, the Do-drul Chorten, and the bazaar area — are within walking distance of each other, though the hills will slow you down.