The nearest airport to Sasan Gir is Keshod (86 kms). There are flights to to and from Mumbai via Porbandar.
The Sasan station is a 10 minutes walk from the Forest Lodge. From Junagarh to Sasan Gir, the train takes 3 hours (goes up to Delwada near Div and then returns to Junagarh, so it is possible to visit for the day). The route is very attractive - Talala is
the last major station 15 kms before Sasan, so stock up with biscuits/fruit/drinks from here. There are two trains from Veraval to Khijadiya and back.
There are bus services from Junagarh, (54 kms) and Veraval (40 kms). There are also frequent buses from Ahmedabad.