Seems to me the guidelines are the same everywhere because the virus behaves the same everywhere.
For instance, "stay 6 feet apart", and "wear a mask in areas where others are present". If you're in the country, you still need to stay 6 feet apart and wear a mask where others are present, it's just a lot easier to do that in a cornfield than it is in Chicago. The guidelines are the same in both places but in a cornfield, you can stay within the guidelines without doing anything. But if you're in the country and go to the state fair, you need to make sure you're 6 feet apart and wear a mask, just like in the big city.
I agree those guidelines (wear a mask and stay six feet apart) are and should be the same everywhere (although, for some insane reason, even wearing a mask has become a political issue). What I was referring to when I said that we can't necessarily only consider local guidelines when opening up was with respect to gatherings. When is it okay for churches, schools, bars, athletic events, etc to resume? If every local environment stayed static, I think it would make tons of sense for us to have local communities decide that issue based on their own local conditions. However, again, once travel becomes ubiquitous again, those local geographical distinctions start disappearing. All it takes is one infected guy from NYC to fly down to visit a large church or funeral service in a small rural town and he has potentially infected and/or created large numbers of infected people in that small rural community that would not have been created if those communities had the same "gathering" restrictions as NYC and other places. That is why I lean towards more national standards making sense once travel becomes ubiquitous again. All that said, I do not pretend to know the answer here. Those questions are extremely complex. I just wanted to mention that having each locality make their own rules comes with its own flaws too.