I hope you're not into gambling.
The primaries will be a slug fest. I don't thin Palin wants to engage in or be recipient of what will ultimately happen as the candidates jockey for attention and differentiation. Thus I believe she won't enter the primaries. It will be just too messy.
Palin wants to be in control. A 3rd party run will allow her to do that. Plus, she will have an advantage over the battered and tainted R that did go through the primary process described above, especially if it is a less than "pure" selection.
She will capitalize on being "anointed" to save the country with her 3rd party attemtp.