Yep. Powder, ball, patch, lube, cap or flint and gun.
Everything else is just frosting - nice to have, even important, but ...
Traditions rifles: good entry level, not the best. Good quality, not high quality. I think it's a good place to start, but for a couple hundred more you can do much better (Lyman Great Plains Rifle is but one example).
Add the following:
Adjustable powder measure
Worm (patch removal) jag
Screw (ball removal) jag
Range rod (heavy duty)
Something to carry it in