If you wish to use a serial cable, the cable needed to make the connection is the Apple System Peripheral - 8 Cable (retail part number M0197, service part number 590-0552). Part numbers are accurate as of this writing.
By using personal file sharing, you can share information between the two computers. Remember, using the Peripheral 8 serial cable will only let you create a two node network. In other words, you will lose other network services because the LocalTalk port is being used by the serial cable.
For information on connecting a LaserWriter to a Macintosh with a serial cable, search for the Tech Info Library article titled "LaserWriter: Connecting to a Macintosh via Serial Cable."