From what I saw over the years, there isn't really any emphasis put on state residency of applicants. By virtue of geography, most people are living in Ohio at time of application, but there are a number of OOS and international applicants every year and the cohorts have been getting increasingly more diverse.
Don't worry about finding VPH experience specifically. Any regulatory/public health/environmental research experience will count (and really no prior PH experience is required to apply). The biggest benefit of experience is that it separates you from quite a number of applicants who have near zero experience in public health- academic and work experiences included. The program attracts a lot of people who use it as leverage into vet school and who have only a mild interest in public health. While many of those students can still do well and complete the program, there are still some people in almost every cohort who just abandon it once they get accepted to vet school and the director really doesn't like that.
I went into the program right after undergrad with a minor in public health and previous work experience with USDA -APHIS. I was a strong candidate despite having a lower GPA and lower qGRE score.
