About Palin and endorsements: what we've seen so far matches what one would expect in primary elections. An endorsement that receives a fair amount of publicity can, indeed, help a candidate in a multi-candidate, poorly defined field in a low-interest primary election. That's where Palin's two big victories were, in the gubernatorial races in South Carolina and Georgia (although her candidate ultimately failed in the GA runoff). In these types of contests, name recognition alone is probably significant. Beyond that, low-information GOP voters are probably seeking any reliable indication of who the conservative candidate is (or at least they're trying to avoid inadvertently voting for a moderate), and so if they've heard that Palin endorsed a candidate, they can be relatively certain that voting for that candidate won't turn out to be an ideological mistake. The more information voters have, the less any endorsement will mean for them. In other words, the question isn't really whether GOP primary voters are fond of Sarah Palin; it's that voters in general are eager to find shortcuts so that they can avoid the difficult work of researching and evaluating candidates, and with little else available the most publicized endorsement will do. Of course, that means that general election endorsements are not likely to make a difference at all, because voters already have an extremely efficient shortcut: the party label.
(I should say, by the way, that I don't actually know for a fact that Palin's endorsement mattered in the GA and SC races, but it would be consistent with what's been reported along with general ideas of how elections work).
At any rate, if you're in one of these states, remember to vote early, vote often. And I'll quote from a Political Wire tweet: "Polls close in FL and VT at 7 pm ET, in AZ at 9 pm, in OK at 8 pm, in AZ at 9 pm and in AK at 12 am"