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.
She cares more about saving the country than "to be in control". If you really followed Palin, you wouldn't be saying such. Running as an Independent (now), would not be in the best interests of defeating Obama. Everyone knows this.