What do you mean by simple? Seriously.
If getting to stores that have the things you need is a real hassle, then yes. If you mean a web of local politics and gossip that you must negotiate like a trapeze artist, then yes. If you mean a legal system that is not based on the ideas of equal protection, then yes. If you mean basing a lot of political power on knowing decades worth of nuanced personal histories, then yes. If you mean places where you have to pay $100 to get a $75 perscription because all you’ve got is a so-called mom & pop business, then yes.
AFAIK, they had phones in Mayberry, and if Mayberry were portrayed today, they would have internet access, yadda yadda. There are areas around here that do not have cable television/internet. There are places where a complete stranger buying stamps may be asked by the Postal Office clerk to take a $20 bill across the street and change it at the local pharmacy. (That last one happened to me personally.)
Where I was living for the last few years, the Clerk would come to your house to deliver your absentee ballot. Just two or three days ago I delivered some parcel cards & tax maps to a guy who was laid-up from a car wreck.
There are lots & lots of places that are genuinely small towns; but that may not be what people think it is. In M_____ there are people who have been living off welfare for generations and for most there is no hope of improving their lots in life. They have a McDonald’s and it is the best one I’ve ever seen. Why? Because it offers the best opportunities for those who would otherwise excel in other jobs elsewhere. It is a great place to go if you want to get stabbed in a run-down bar. There is a frighteningly significant portion of the population who believe things such as: if you have a venerial disease, the way to cure it is to have sex with a virgin. In the township where I work, which is not as rural as many places by a long-shot, the 2000 Census found that 100% of single mothers with children age 5 or under live below the poverty limit.
Frankly, one of the biggest problems facing small communities is the effort by city folk who re-locate and want to create a vision of Mayberry that simply does not (& cannot) match reality. Every young, single mother lives below the poverty limit?! Hell no we don’t want them to have access to convenient, affordable shopping or jobs for which they may qualify. So Meijers & Wal-Mart, fuck off!
With all that in mind, I have to say that Mayberry never existed anywhere in the world. Some may disagree, but I doubt they were on the target list of the local political machine. Local politics is just as nasty as in the big city without the advantage of having the economies of scale necessary to support the professional protectors of individual rights. Justin Volpe would have much better odds of not being caught in Mayberry than he would in New York, IMO.
I don’t know if that helps the OP, but that’s the only answer I can offer.