You’ll need to set up port forwarding.
Assume that the pcWRT router WAN side IP address is 192.168.101.100. And the printer IP address is: 192.168.102.200, printer port is 9100.
If you haven’t done it already, give the printer a name on the pcWRT router, for example, click the printer hostname on the Status page and name it printer.lan. The hostname should display in blue after you saved a name for the printer.
Next, go to the Network Settings page. In the Port Forwards section, click Add. Enter these values in the popup:
1. Name: Printer port forward (or anything meaningful)
2. Protocol: tcp
3. External Port: 9100
4. Internal Address: pick the printer (192.168.102.200)
5. Internal Port: 9100
Click OK, then Save.
On your PC, configure the printer to use the pcWRT router IP address (192.168.101.100) and port 9100.