Oh, the one way ticket I know little about. BUT a traveler just did it to my house. Hans from Norway. He is on the road now.
I believe he said they only gave him a 90 day stretch when he entered.
It's good to have a destination address and a travel itinerary, but yes it can be done.
Hans is Hansi on here, you may find him somewhere.
I have helped four this year alone.
James and Colleen Tucker.
Aut viam inveniam aut faciam
Beat our time, Los Angeles to Ushuaia 70 days