The first non factory "kit" I built was from Pecatonica River. Sense those days, I've built over 12 of their different rifles.
Dick Greensides, the owner of PR produces some of the best rifle and pistol kits around.
The stocks sold by Track of the Wolf are made by Dick and his prices are generally less expensive.
As was mentioned, he grades his Curly Maple lower than many other companies so even the lower #2 and #3 grades are nicely striped. I usually order the #3 and have never been disappointed.
His fees for cutting dovetails and installing breechplugs are exceptionally low.
Although he will install the buttplate, I suggest that you save this job for yourself so that you can make the length of pull correct for your body.
If you decide to go whole hog and buy a rifle with a swamped barrel, by all means pay him the extra little bit to cut the barrel channel. It is well worth it.
As for the difficulty, these guns require some knowledge on the part of the builder.
The screw holes are not drilled or threaded, the stock has a lot of wood that needs to be removed, many things like the sideplate, trigger guard, butt plate etc are rough sand castings that require filing, sanding and polishing as well as inletting them into the wood in the right place.
If you decide to build one of these, first, before you order any parts invest in one of the many books that describe all of the steps. They (it) will pay off in both the short and the long run.
(An excellent book is "The Art of Building the Pennsylvania Longrifle".
zonie