I’m from Asia and we don’t do much of country wedding however I read a little about it previously.
As a bride, you definitely have to walk down the aisle with your favorite pair of cowboy boots and a white long gown. casual -formal wear for the groom with cowboy shoe and hat.
The suggestion on venue would be your backyard, barn or at a farm. Yes farm!
Using of wheat centerpiece is classic yet simple and elegant! Alternatively, you may use old milk can/bottles with some daisies and elderberry or having wild flowers.
Chairs and dinner set up must be wood , beer barrel are good for table set up. handmade quilts as table runner.
and wouldn’t it be perfect if you arrive at the reception on a horse.
just my suggestion and i hope it helps!