Wireless Joint

Is it possible to have an Access Point Name that works with all US carriers, an APN that can be effectively carrier agnostic?

Still assembling my first router. Please excuse my goofball rookie questions.

Nope. The carriers use APNs as access names to their networks. There are no universal APN names. There ARE modems that are getting better at auto loading the APN for you. I can leave the APN blank and it will connect anyway, on some modems.