Rent mailboxes / addresses from executive suites in that area. They usually cost $25 per month. Add on a phone number with the local area code as well if possible. Don't use Google voice. Have all of the mail and phones forward to your main phone and address.
Create Google Places profiles for each using these addresses. Optimize them with unique business information. Verify these profiles via phone or address. (Most likely address) For the URL for the profiles, have them go to specific pages (which is the next step).
Create dedicated pages for each location. Create optimized content for each. Use Schema.org or hCard to markup the addresses. Make it consistent with your Google Places page.
Create local citations in local search platforms and local directories for all of your locations. Make sure the business name, address, and phone number (NAP) are consistent with the ones you've purchased. Use distribution services and citation checkers like Localeze and GetListed. Get reviews to your Google places page. LEGITIMATE REVIEWS!
I have done this successfully with two clients now. Penguin won't really let you rank for them now organically, but locally you definitely have a shot.