And Scott Wilson
Lori and Merle are dead so that leaves two slots and the Governor will likely be mutilated by Andrea and presumed dead by everyone; Woodbury wouldn't be major location and the Governor wouldn't reappear until the mid-season finale which leaves a third slot.
So I added Carol, Tyreese, and Hershel. Since season 4 will likely see the demise of Carol and Hershel, they should have a lot of screentime in their final season. And yes, I do think that tomorrow night's finale will only see the death of Allen. Sasha and Milton are both maybes and I think everyone else is safe. So who would be your ideal season 4 main cast?