Shillong is just 100 kms away from Guwahati. All modes of transport are available - car, bus , bike, flight and helicopter. The most fun and convenient way is to travel by renting private car will will cost around ₹2500/- If you want the most economical and convenient way to travel to Shillong from Guwahati is by bus which will cost you around  ₹180/- only. If there is no time in your hand, then take flight which will cost you around ₹2500-3500/-.