From Lumbini you catch a local bus back to Birovar(something like this) for 40rup. We tried 2 ride ou top of the bus where you are basically riding on the roof racks..not really allowed by police but since we're tourists we could.. locals do it too..they are just asked to get down by the police.
From here you wait for a local jeep to take you to Sonauli for 10rup. You can take a tuk-tuk for 80rup but it is a short easy drive in the jeep anyway.
Here you go thru Neapal and India immigration. You can walk this! Then there are buses (tourist or local) to Delhi, Varanassi, Ghoreaphur. We took a 4hr local ride to Ghoreaphur for 56rup. In this city you can then catch trains or buses to nearly anywhere.
No trains available today so we took an 18hr local bus to Agra.. 360rup each bit more expensive than the train but we wanted to be on our way. The locals here really helped us..Giving us 3 seats so we could take turns to sleep. They were so nice always getting others to sit somewhere else if there was space.
Again I say the country has its problems and craziness, but there seems to always be nice people who do look out for you.
Ciao for now....