Pokhara is 200 km from Kathmandu, 78 km from Sunauli (Nepal/India southern border) and 72 km from the northern border. Basically, there are two options for getting into Pokhara, either via land or by flight. By flight, there is only flight from Jomsom and Kathmandu which normally takes 25 minutes.
By land, it takes 5-6 hours from Kathmandu depending upon the traffic on the highway in between Kathmandu and Pokhara. From Chitwan, it’s a 6 hours overland ride. Tourist buses ply in between Kathmandu, Pokhara, and Chitwan. For more luxury ride, one can hire a private vehicle which comes bit expensive than buses. There are also regular buses from Sunauli, Kakadvitta, Birgunj, Nepalgunj and Mahendranagar.