I have to wonder how many of the big cats seen in the east were bought as pets (legal if they are under 6 months old) then released or escaped into the wild when they become too much to care for. Cats seen by people do not nessesarily equal a breeding sustained population in a given area.
A number of years back, remains were found in Massachussets that started quite a stir, turned out that the cat had been de-clawed or some such. There was something like that about the remains that showed it to be a released animal.
Bear in mind, radio tracking of cougars (in CO I think) showed cats roaming 600 miles. I don't know how many cats were in the study or how typical that really is, but if one cat may travel 600 miles, another may go further. No real knowing. Cats seen in VA could conceavably be Florida cats. I know it's impossable to prove a negative, but at the same time there is no real proof that there are populations of cats in many, many places where the locals will swear up and down that "they're here! I SAW one!"