Without the password, I think you're stuck, though I'm not certain because my home machines began with System 7 (I used System 6 at work).
You can download 6.0.8 from Apple.
This page at Low End Mac discusses it. The problem probably would be getting the system onto floppies. A single floppy, though, can contain a stripped-down System 6 (which I did use) that will boot the machine (if the floppy is the so-called high-density, anyway — and the machine can read high-densities).
If I remember correctly, the Mac first scans for a system in the floppy drive, and if it finds one, it boots from that. From there, you might be able to do an end run around the password or simply trash the system if you have another one you can load.
From Low End Mac regarding dowloads:
Software is stuffed and requires an expander, such as StuffIt Expander (which comes with most web browsers). Mounting disk images or making floppies from them requires Disk Copy (download Disk Copy) or MountImage.