I have the Early Lancaster kit.
The stock was probably 95% inletted. It's their standard wood, which is probably equal to a grade 5 from anybody else. You have to square off the end of the barrel channel where the breech is, and inlet the tang. Inletting the lock and sideplate, and the trigger plate are a piece of cake, as the pre-inlet mortices are extremely close.
The barrel comes dovetailed for everything except the rear sight. However... if you ask, and tell them where you want it, I'm sure you could get Jim to dovetail the rear sight as well, as he did that for me, although, I was there when he did it. You will have to clean up the dovetails with a safe-sided triangle file, just a tiny little bit. You will have to cut the slots for the underlugs in the stock, and drill them for the barrel pins. You will have to inlet the ramrod pipes and the end of the stock for the muzzlecap. You will also have to fit the buttplate (the hardest part of the build in my opinion). That end-grain wood on the butt is just a real PITA to work with.
Mine came with the wooden patchbox kit, which I have not installed yet, but shouldn't be too difficult, as it's already dovetailed into the stock, I just have to shape it up and tack some brass onto the end of it, then add the little release.
Once I've finished adding the hardware, sanding and shaping the stock will be a piece of cake as it's already so close to finished. There's one small block of wood to remove just in front of the lock that is used to hold the gun in a vise while you're working on it. The rest will just be sanding.
The DVD helps a lot... as do the recommended books up above. I would also recommend The Gunsmith of Grenville County, an excellent book on this stuff as well.
I hope this helps. If you have any more questions, please feel free to ask.
Here's a couple of pictures of my progress if you're interested: