I'm not sure what the law is in Alaska, but she could probably appoint herself to replace Stevens when he goes to jail, and this could keep her in the news and in the public's mind, but being in the Senate does not give the experience that an "executive branch" position like Governor does.
Plus, The GOP has not had much luck running Senators for President.
Alaska changed the law after then-Governor Murkowski appointed his own daughter to succeed him in the Senate. Now, a special election must be held within 90 days of a vacancy to fill the unexired term of a US Senator in Alaska.