Assuming ramrod hole and channel are done, buttplate would be next for me. I hold off on thimbles until near the end of the build, after I have shaped the forestock, which is much later in my builds, one of the last tasks I do.
Once I had the buttplate inlet, I would then rough-shape the buttstock to locate the wrist, and rough it in. This tells me where the tails of the lock and sideplate should terminate, and that area gets defined. But it isn't until I have the buttstock, wrist and lock panels defined that I ever touch either the upper or lower forestock. In fact, I usually get these areas pretty much to a finished state before looking to the forestock. By finished, I mean plain finished, no embellishment or carving.
