As someone who one ran frantically to the departure gate at the Memphis airport only to find out when I got to the gate that my flight left not in ten minutes but in 70 minutes because, unbeknownst to me, Memphis (unlike East Tennessee) is in Central Time, I can’t say that I’m a fan of states (much less counties) being divided between time zones. And if the crack of dawn in Nashville is around 4:50 a.m. in June *even with Daylight Saving Time*, then clearly all of Tennessee should be on Eastern Time (along with all of MI, IN, KY and FL and the state of AL); New England probably should be on Atlantic Time.
It’s funny that you have to drive for 2 days straight to the west (to the New Mexico border) to get to Mountain Time. Tennessee, of course, is a long state (about 8-9 driving hours from Memphis to Mountain City excluding the hour time change). The eastern part clearly should be, as it is, in Eastern Time. How far west that should extend is a debatable issue.
You probably know that Newfoundland has its own time zone, a half hour ahead of Atlantic Time, which has to be confusing as hell to adjust for.