I went Lumbini once, Though my family lives in Nepal, I hardly fully explored Nepal, and one such destination was Lumbini the Birthplace of Lord Buddha. The place is located nearby from Bhairawa, from India one can go Sonauli Border then direct to Lumbini.
The place is full of temples and natural greenery. All the structures of Lord Buddha Temples that world have are constructed there.
The temples are so beautiful that you never want to get out of there.
Also one can buy special handmade handicrafts and so amazing things there which are related to Lord Buddha and other Gods.
For local sightseeing there is not much apart from Lumbini itself but yeah if you have time you can reach Pokhra, most beautiful place in Nepal which is known for its sanitation and Lake.
One can easily get hotel there in affordable rates but it is always advisable to book prior to visit.
The place is full of safety.