Hi Travis,
You need config default route on the sco-unix box point to the inside interface of the PIX 501.
If the Sco-unix box default gateway is not PIX inside interface.
I assume that the VPN client pool is 192.168.1.1 to 192.168.1.254
Put a static route in the Unix box:
ip route 192.168.1.0 255.255.255.0
Best Regards,