No furnace is not a big deal by itself, but likely no windows, no wiring, no plumbing, no fixtures. What remains likely has mold, lead paint, and other hazards. It's at best a gut-to-the-frame-and-rebuild. If severely weather damaged it might even be a tear-down.
The Google Street view [1] shows it needs at least new doors and windows. Maybe even a new outer wall on the second floor (or the very least the ivy removed before it does more damage).
