Mailing a letter information in the USA?

Hello Everyone, I have a question. I want to mail a letter to my dear friend for his birthday. The problem is, he currently doesn't an official home address and I was wondering can I mail a letter to his local mail postage with out a P.O box . Then from there he can pick up the letter for any additional fees or anything? I currently live in Los Angeles and he lives in Las Vegas, Nevada. How can I do this?