How did Diary-Riddle hope to come back?

Question

In Slytherincess' wonderful answer she explains that

The soul piece cannot live without a receptacle to hold it; if there were no receptive person to latch onto, the piece of soul would presumably die.

If this is true, and from Hermione's quote on that answer that seems almost certain, how did Tom Riddle from the diary-horcrux expect to 'come back'? Did he expect to permanently possess Ginny? Or was he expecting to form his body back a la the real Voldemort with a potion? None of these options seem plausible, yet Riddle seem a) confident he could come back and b) aware of his limitations.

Answer 1

JKR opined that if Harry didn't save Ginny, the real Voldemort would have gotten stronger. I read that as the diary soul fragment would somehow rejoin the main soul fragment.

From http://www.jkrowling.com/textonly/en/faq_view.cfm?id=17:

Q: In 'Chamber of Secrets', what would have happened if Ginny had died and Tom Riddle had escaped the diary?

A: I can’t answer that fully until all seven books are finished, but it would have strengthened the present-day Voldemort considerably.