I guess my first question would be: do you have a need that device can fill, or are you looking to take on a project for some other reason (education, boredom, etc.)?

I honestly don’t see to what great use a router (and modem) that was discontinued a decade ago can be put that couldn’t be accomplished with less complication and less power draw by using a modern device. I’m not trying to rain on your parade, but knowing nothing else about your situation I don’t know that I can see any utility in a device like that anymore.