The only way you are allowed a campfire at FW is in a fully enclosed fire pit that you would have to supply. There are times when even these are not allowed due to dry conditions. FW does not sell firewood.
I'm sure a lot of other people might jump in here but for the most part campfires are not allowed at the Fort. They have a charcoal grill available for you at the site and a nightly campfire with chip and dale where you can go and toast marshmallows. I have seen some people talk about using covered portable fire pits but I don't know the official view on these. There was no firewood for sale for these at Fort Wilderness last week.
The only way you are allowed a campfire at FW is in a fully enclosed fire pit that you would have to supply. There are times when even these are not allowed due to dry conditions. FW does not sell firewood.
Not sure of the policy but i do know i saw signs saying not to use firewood from other areas of the country. To only use local woods due to insect reasons.