i had a nepali who tried to get into canada and get a visa to US while returning. he was mentioning me that getting an appointment for the interview is tough. i am not sure if that's the case for all kinds of interviewee or certain types only. he was trying hard to get an appointment as he mentioned me that it might be "comparatively" easier to get visa from embassy at canada than one in nepal. BUT hey, everyone knows that nepal ko visa k ho k ho. thegan nai hudaina k huncha bhanera.
also what i have heard that in case u want to get a new visa at ktm, you can set up an interview from US too, but your physical body has to be there (probably nabil bank) to confirm the appointment before the interview happens.