i dont know if nepal qualifies for drop box so you might need to attend in person interview . india definitely qualifies for drop box but not sure about Nepal . one thing is sure that you might have to face administrative processing which might delay your visa approval . normally 1 week to few months . administrative processing is simply a background check which takes 7 days for some and months for others.

few weeks back some of us went to Mexico for first time h1b visa stamp . process was smooth, passport returned in 3 days . i did not participate in the process as im a GC . to my knowledge my advise would be if you are going nepal, dont plan for 2 weeks visit . make at least a month vacation and be prepare if your process gets a bit long . i don't know how they chose people for detail background check because they don't disclose . once your passport gets in admin processing there is no choice but wait .