Possible Spin-Off

As I've thought about what will happen in TWD, I remembered what Rick said about rebuilding society and creating a world that Carl could grow up in. It got me thinking about a spin-off set years after most of the characters (save for maybe one or two survivors) are dead for whatever reason that would show a 20-30-something year old Carl leading his own group. They could clear out herds of Zombies to colonize territories, and maybe his group could even travel overseas at some point to establish trade relations similar to what the Safe Zone and the Hilltop have tried to do. I'd always been curious about how or even if the rest of the world was affected by the outbreak. I wrote a letter to Kirkman about all of this and never heard back, so I'm hoping to find out whether these are the stupidest ideas any of you have ever heard or if might be on to something?