Wrong! Wrong! Wrong! :)
I don't think he was ambivilent at all in the book else he wouldn't have said to Gandalf that he has worked hard throughout the long years to do something foolish with the Palantir.
His objective was to keep the free lands free, not come to (his own) power as quickly as possible. If it meant defending the hobbits while Bilbo held the ring or waiting to claim the crown until after the foes of Gondor were defeated then so be it.