I actually fear the Rinos and non-elected Republican elites more than the Rats concerning Sarah. They will play along for a while and try to appear conservative. When the situation gets critical, that’s when they stab you in the back, examples: Joe Miller and Christine O’Donnell.
When you're an up-and-coming hopeful in politics, your fate is pretty much in the hands of powerful backers and party honchos. Much less so, when you're an established power broker yourself, such as Sarah is. She has built herself into perhaps the most important and powerful person in the Republican party.
Sarah will be far less reliant on the party establishment, than a newcomer would be, so there won't be as much chance of her being betrayed by any of them.