We're told that less than half of Wasteland 2 is currently available in the beta accessible via Steam Early Access. A new update coming next week will increase the game world significantly, adding to the beta "most of the Arizona portion of the game."
Last week developer inXile Entertainment discussed the length of the game, pegging it around 50 hours, and talked about the second half of the game, which will take place in Los Angeles. It will be a "separate world map from Arizona."
The Arizona update is due to arrive next week. The Wasteland 2 beta is available now via Steam Early Access.