Try these:
https://www.marylmartin.com/
She is a postcard dealer and runs a show and lists shows on her site. I bought a large group of 1932 winter Olympic RPPC's from her last April in Allentown.
It is too bad you are down south. The Allentown (PA) Paper show every April and October has quite a few pc dealers. There is also a large PC show in York, PA and a smaller one in Havre de Grace, MD.
There is also the International Federation of Postcard dealers which is mainly U.S.:
https://ifpd.info/
Here is a postcard and ephemera dealer from Germany. I have purchased a few items from them. They are very good and send emails when there are new items in the categories I purchase. They also send emails when they are having sales to reduce 'stale' inventory.
https://www.ansichtskartenversand.co...dex.php?lang=2