> for mail I send, none of it is scheduled for 2-day to Virginia even though I'm very close to the border (50 miles?), but for mail I receive, half of Virginia is in the 2-day zone.
I think the sweet spot for sending is to be in an area that is busy enough that the USPS is essentially running 24/7 behind the scenes, but not busy enough that they can't keep up with mail volume.
I used to live in downtown Chicago and (pre-pandemic at least) the main post office had a manned counter open until 11pm every day. You could drop off a package at 10:30pm, check the tracking info when you woke up the next morning, and discover that it arrived at the giant sorting facility near O'Hare 45 minutes after you dropped it off, was put on a truck an hour later, arrived at a facility out of state at 3am, and was already on another truck heading to its final destination.
I've been eyeballing a number of locations. It looks like Wichita, KS might be the best sending location. Not a single spot in the continental US that is more than 4 days. Kansas City has a tiny spot in Northern California that is 5 days. As far as the really large cities go, Dallas, Chicago, and Denver are really quite good.