Hi CIRE! Welcome to the forum. In this section of the forum there is a sticky titled "A Game Plan for Beginning Signing up for Shops." There are suggestions of companies that have shops nationwide so I'm sure you will find some in your area. That post is a few years old by now and Service Intelligence became In Touch Insights and Corporate Research became Stericycle or some such, but I know that Bare International has nationwide shops.
Resources for finding work also include Jobslinger.com at the free version. When you put in your zip code you will see jobs posted for your area. Be aware that most of the jobs you see have been taken already by other shoppers so the real value here to you is to know what companies to register with and to see what kinds of jobs they are posting. Mystery shops are generally repeated every month or quarterly, though some clients have themselves shopped weekly or even more frequently. You then can find links to register with them at the bottom of each forum page here in the "Official List of Mystery Shopping Companies".
There is also a job board here where you may occasionally spot a job in your area of interest.