I've been quite surprised at how durable cro-mo bikes can be. I've rescued several from years of outdoor abuse and found only surface rust that came off easily with steel wool. The chain certainly needs replacing but cogs and chainrings and rims and such are possibly just a quick polish away form being fine. I just recently restored a tandem whose fenders looked to be solid rust. I rubbed a small section just on a whim and it magically became shiny chrome again. Try a good cleaning first.