If you restore to that configuration everything should be fine. You can do this in two steps:
Connect your D-Link router to the Internet as you usually do. Make sure that your Internet works when connecting directly to your D-Link router. As usual, to avoid IP address conflict, set your D-Link’s LAN IP address to 192.168.2.1.
Connect the pcWRT: connect from a D-Link LAN port to the pcWRT WAN port. Leave pcWRT’s WAN connection on DHCP client.
No need to worry about DMZ, port forwarding on the D-Link router. If there are existing entries, remove them.
No need to worry about UPnP, DNS or NAT on either D-Link or pcWRT.