If you have to ask.... Seriously it sounds like the indecision is stemming from your equal valuation of your career/home and your relationship. What this means is, you can't figure out which one is more important. I doubt you will be displeased with SC, the good 'ol dirty south, but then again if your surroundings are that important to you, then you have to decide this - how much personal, mental, intellectual, spiritual, emotion, financial gain would you project from moving to where you want to move (without your girlfriend), or moving with her?
If you move away from her, one of two things will happen. You will either miss her and regret it, and it will be very hard to undo a newly started life, or you will be glad that you made the move for yourself and your personal gain. If you go with her, you might either regret it in the back of your head for a long time, or you may end up really liking SC, in which you win because you are still with your girl.
So, for the nutshell approach - is she more important, or is the possibility of your personal gain from moving to Vegas more important to you. And which might reap greater rewards in the end.
Before we got engaged my wife went off to school across state. We saw each other every weekend and talked on the phone when we couldn't see each other. In our case, absence made the heart grow fonder and we eventually (obviously) ended up getting married.
If you are a spiritual person, I would suggest praying about. Actually, I would suggest that even if you aren't. You would really be suprised how God guides the faithful.