I feel like Lynchburg would be the best candidate. Did you choose Danville because it was the final Capital of the CSA in otl?
Exactly - it struck me that this sort of allusion would be very much in the style of The Dean.
interesting ideas! my personal TL-191 fix-up has both governments staying in Richmond, largely because I liked the idea of all the different little groups (Fire-Eaters, pantomime Cavaliers, crypto-Unionist Uplanders, military industrialists, unpaid soldiers, Black militiamen led by Gen. Longstreet, deranged job-seekers hiding pistols, petitioners, cutpurses, sporadic Sumner-style beatings) typically tripping one another up with nobody around to make them behave
it'd also highlight how reliant the CS Congress is on one state to protect them, unlike in the US system
Given that Richmond is still the national capital either way, one suspects it would have more than it's fair share of loons and other enthusiasts, whether it's part of the Old Dominion or what I've come to think of as the 'District of Jefferson' (A nod to Thomas Jefferson and to Jefferson Davis): either way there's plenty of room for Government by the Heavy Mob!
On a slightly more serious note, I would be interested in seeing a map that showed the 'No more than 10 square miles' limit around Richmond's Capitol so that we have a rough base on which to sketch the Timeline 191 version of Richmond (Which would, in all likelihood, be strikingly different from our own): it's also interesting to wonder just where the various offices of the US Government would be placed in de facto capital Philadelphia (not to mention speculate on just how many of them would be purpose-built).