Focusing on just Palin's own background, Sarah Palin is from the Radical Right.
She has not pushed it as governor of Alaska, but she during her campaign for governor in 2006, she thought creationism should be taught in schools (!!!!). See:
Sarah Palin is way too extreme to have her a heartbeat away from being President. And McCain would be the oldest President to have ever assumed office. Hopefully their winter-spring "romance" won't bear fruit.