I don't even want to think about The Walking Dead coming to an end. Love the show and story lines.
If I had to create an ending it would be the main characters continually moving around until they find their 'Home' which would be a place they built. They would acquire a scientist to their group and she would work on an antidote for those who get bit. Once bitten they give the medicine and it doesn't stop the change in them physically but mentally it keeps them able to coexist with the group. The 'Changers' would live side by side with the group but would still need to be watched. So going forward- whatever left of mankind would still survive with old and new zombies.