said by Lanik:I see in that case if you want to by pass NAT all together and use this device as switch/AP take the cable out of WAN port and plug into any of LAN ports, now its switch/AP.
Well, it is half of what I'm looking for. That doesn't solve the requirement for DHCP with a gateway being some other device (in fact it won't give a valid/useable DHCP lease since it thinks that it will be the gateway -- to nowhere since the WAN port will be unconnected).
It is sounding like my only possible solution, without completely reconfiguring my network, is to use this box as a switch/AP, shut its DHCP server down and get some other device (on one of the LAN ports) to act as the DHCP server (and gateway).