In EPISODE 7, I'm going to predict that Han Solo and Princess Leia are separated and have lived apart for many years.  Luke and Leia get abducted and are held hostage.  Han will now be like those John Wayne characters the Duke played later in his career... the estranged, almost over the hill loner who saddles up one last time to make things right.   But he can't do it alone.  That's where the newer characters come in.  I could even see Han dying at the end.   

I wouldn't be surprised if the way they got Harrison Ford to come back was the same way they got Leonard Nimoy to play Spock again in STAR TREK II -- offer him a big dramatic heroic send-off.