Is your old circle of friends still around and active? Do you still want to continue with Rinoa's story or do you want to go a new direction with her? Hell do you even want to keep her backstory the same?  I think those questions need some answers before you can really move forward with that particular character. After that its just a matter of writing yourself a story for why she disappeared and what she has been doing since then if you are trying to pick up with old friends etc.. But If you are having more fun with the new character why push yourself to use your old character?
