Sarah Plain can work the conservative speaker's circuit and make a living from speaker's fees through the next election. After that requests will come less often, even the tabloids will lose interest, and eventually someone in the Palin family will need to get a job. Maybe she can eke out a few more years on the church circuit, but I don't know what speaker's fees are like on the religious right.
Her brand is so tarnished on the national stage it is hard to imagine her coming back. Perhaps Fox News will give her a paid seat as a commentator or host in the run-up to the next election? Or she can hire a ghostwriter and try to make it is a less-vicious, intellectually vapid version of Ann Coulter. The odds on her success are quite long with both those scenarios, but she can try.
Fortunately for this country being an elected official will no longer be an option for Sarah Palin. There is no way she can survive her post-election performance as a Governor and her decision to step down. Her career as an elected official is completely over. Now she has no track record and no home base of operation. Just ask Rudy Giuliani how difficult it is to run for national office when your home state loathes you.