I dont think its such a terrible idea than you think itll be. Yes the expenses will be so much more than shes paying now but if she really wants to pursue her career path then i say go for it. In reality they might not advance their careers at all but they definitely increase their possibilities of meeting new people to boost or help them in some ways. The commute will suck but you can get used to it. Honestly the reason it might be too big is because your worried of the change and it is your girlfriend so i wouldnt be surprised if your just being protective. As long as shes willing to pay 1,000 something a month towards rent and make it work then she'll be fine.