Follow exactly what Bairagikancho said and you should be good. In terms of sticker from Dept of Labor, you need that in your passport before leaving TIA. Is it a hassle? Probabaly yes (since) it will take a whole day for you and you know how administrative things work in Nepal but not a impossible task. The place was somewhere near Tinkune last time when I did it.
To make things easier for you there will be lot of middle men waiting for you to help if you know what I mean.

All in all you should be just fine.