A conservative from South Dakota would get little advantage from being from South Dakota. The Plains states north of Oklahoma have only seventeen electoral votes between them and sixteen are best described as sure things for any Republican nominee. (NE-02 is not a sure thing unless the State of Nebraska reapportions its Congressional seats to split Greater Omaha, which I think unlikely). Several States themselves have 16 or more electoral votes.
Now contrast Mike Huckabee, should he run for President; he takes the Inner Arc and about 35 electoral votes completely out of contention for Obama. Thune might have to work to solidify those states for himself; Huckabee could expend his efforts elsewhere more profitably for his campaign. I am not saying that Thune doesn't eventually win those states, but such a benefit as Huckabee has in being from an electorally-important region of the country is that he can spend more time in places like Florida, Indiana, Ohio, and Virginia where neither Huckabee nor Thune has no particular strength.
You are far too fixated on the home state or "home region" a candidate comes from. It doesn't really make much difference these days. The fact that Obama's home state was Illinois and McCain's home state was Arizona wasn't much of a factor outside of Illinois and Arizona. Heck, I would guess that a non-negligible fraction of voters wouldn't even have been able to tell you what the candidates' home states are.