I fished Greenbrier several years back - the stream on the property is called Howard's Creek. It's a super-simple stocked stream - looks like it was an existing spring creek, and they dug out a bunch of pools to create easy spots. Not a ton of flow when I went, but it might be better now. You'd be fine with woolly buggers, a couple of attractor nymphs, some terrestrials, and maybe some sulphurs. 4 or 5 weight is fine. 4-6x tippet.
There's a little excursion shop in the resort that has a small selection of flies & basic gear, and you have to go through them to reserve time on the water.
Off-property, the lower end of Howard Creek meets up with the Greenbrier river. That lower section of Howard's was pretty easy wading, and was absolutely full of 6-10 inch smallmouth bass. Minnows, poppers, nymphs - typical SMB fare is fine. The main river is supposed to be decent fishing, but I was wading, so didn't cover enough water to get a full read on it. Canoe rentals are available in the area.