I have a 34 unit in a town of about 2400 but my Metro is Cincinnati, Ohio which has a total population of over 2 million. Lots of jobs my folks can commute to if they don't work local to the park. I do just fine, but do have to keep my homes in the lower price range and my lot rent is lower at $230 per month (residents pay all utilities separately too the city )while others lot rents in the heart of the metro are over $400. This is an advantage and disadvantage in that my residents know there is a cost benefit to living in the small town.
As mhp stated above, there is a nice homey feel to the small town and it's easy to get friendly with the city officials and utility company workers. We have received great cooperation as we worked hard on turning our little park around and we have gotten a lot of complements from those city folks. They like us because they love their little town and we've helped improve it.
I have to work a little harder to fill my lots and I do this by advertising on homes for sale or rent and yardsale type facebook groups. Craigslist doesn't get geographically specific enough for me, but Facebook groups can be city and/or county specific and that is where we have been most successful in advertising. We only have 1 RTO available at this time and our lots are 100% occupied.