I agree, and recommend NRNTN highly. John & Lisa Brittain are friends.
They have perhaps the most extensive collection of northern/far
northern pecans, hickories, black walnuts, butternuts, Carpathian
walnuts, persimmon and pawpaw varieties you'll find anywhere.
But, again, I'm not certain that I'd recommend many, if any, of the
northern/midwestern/far northern pecan varieties for the hot humid
Southeastern US, where they get sufficient heat units/growing degree
days for the large Southern type pecans to mature and fill their nuts.