The ideal endgame was a ring of defensible islands through the Pacific and access to the oil and other resources of China, SE Asia and the Dutch East Indies. The hope was that a decisive strike and followups on the US Navy would break US morale and force a peace treaty setting up Japanese/American spheres of influence including Japanese access to the resources they desired.

Here are some great and more in-depth discussions:

http://www.reddit.com/r/AskHistorians/comments/23mjp3/what_was_japans_longterm_plan_when_they_attacked/ http://www.reddit.com/r/AskHistorians/wiki/wwii#wiki_japan_and_pearl_harbor