Thanks for your reply, skyeci.
So, to be clear, and assuming that everything will work as I hope it to, I won't be able to connect directly to my PC through lan2 of the 612, I'll have to connect it to the Asus?
Also, will changing the IP address of the Asus be simply a matter of going into the WAN settings and just changing the numbers to, say, 192.168.1.254? It occurs to me I'll have to do this anyway in order to change device names connected wirelessly.
Also, I've assumed that connecting the 612 to the Asus via the Asus WAN port bypasses the dsl side of the Asus. Is that not right?
And also, on my current set up, has the lan4 port on the TG582n been re-assigned as a WAN port?
Sorry for the questions, just trying to learn.