Ben, great question. When I was applying to jobs, I also was interested in getting out of where I went to school (Washington D.C.) but encountered some of the same hurdles that you seem to be facing. Now I do not know if you are applying to large firms and companies that do advertising, but I would encourage you to do so if you are looking into breaking into other job markets across the country. While smaller boutique firms can be a great experience, chances are that they do not have as many locations and internal mobility will be difficult. Large firms and companies have locations all around the country/world and mobility geographically and within the company is much easier to do as they are more familiar with the process.
When you apply to jobs, be sure to note on the application your willingness to travel and relocate. On all the job applications that I filled out, there was a question about willingness to relocate as well as willingness to travel. Always fill out this question as it is one of the ways that companies gauge your flexibility; the more flexible and adaptable you are the better. I told my company that I am willing to travel up to 100% of the time and am willing to move anywhere geographically; this doesn't mean that I will travelling all the time, it just affords me the chance to do so if an opportunity comes up.
If you get contacted by a recruiter via phone/email, be sure to tell them your desires. The recruiter is the person who is going to be advocating for you so there is no way for the company know your desire to break out of the Bay Area unless you tell the recruiter. If possible tell your recruiter multiple times your wishes so as to really get the message across; don't call and harass your recruiter daily, but if they call you be sure to emphasize your willingness to relocate. I had 4 phone calls with my recruiter at PwC and I told him every time about my willingness to travel and move.
I hope this helps and I wish you the best of luck!!