I am going to Nepal soon, and I have AP under TPS.
What are the steps (documents) that I need at the TSA, Airport (airlines) and same while coming back from Nepal?

While Going to Nepal
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I have old paper i-94, where should I surrender that?
At TSA, are AP and my passport enough to get through the security?
What are the documents that I need to show to airlines (china southern) people to get into the plane?
I have connection in China, any problems there?
What are the documents do I need to show at the KTM airport.

Coming Back to USA
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What are the documents that I need at the KTM airport to fly the Plane.
What are the documents do I need to show at the USA port of entry?

Any extra documents/proof that I should take with me for in case?

Any Information will be greatly appreciated.
Thanks