I've built over 10 rifles from Pecatonica River.
Each one is a different style (Lancaster, Reading, Bedford, etc.).
The curly maple they supply is consistently excellent.
Most of their "kits" come with straight octagon barrels but on many of their models they offer swamped barrels and they will cut the stock for it.
The prices they charge for doing extras like cutting sight dovetails, installing breech plugs etc. are very reasonable and are always less expensive than the local gunsmiths in my area charge for similar work.
The parts they supply are in their rough condition. That is, the castings are "as cast", often showing their sand cast surfaces.
All of the parts will require work to get them to a usable condition.
None of the threaded holes exist so you will have to locate them, drill them, tap the threads and enlarge the clearance holes.
The only things that are in a "usable" condition are the lock and the set triggers.
Even these will require the screw holes that hold them in the stock to be made by you.
In other words, these are not the easy kits available from Traditions, Lyman, etc that take 20-30 hours to finish.
Typically they will take over 150 hours of work.