From a hardware standpoint the only requirement for a serial RS232 connection to the printer would be a null modem cable. On an AppleTalk network, you can connect via the printer's LocalTalk port. Use NeXTSTEP 3.0 which reportedly includes an Appleshare client which provides access to PostScript printers on an AppleTalk network.
On the LaserWriter Pro itself, you want to set the thumbwheel switch to position 0 which sets the printer for PostScript, 9600 baud, 8 data bits, 1 stop bit, and XON/OXFF handshaking.