I feel a little stupid replying to this thread because I don't have any real info for you. Maybe it is a little too late to think right. All I can add to this convo is that I have a SMC7004ABR router that I got to print using cups. I forget how I did it and do not have time to attempt to recreate it. Just thought I would tell you that it is possible. I found the answer with extensive googling.

Good luck,
Duffin