Ditto... the GPR is a good one to start with. Just enough work to get you a bit of a feel and learn a few skills without the risk of ruining $600 worth of parts.
Also you end up with a solid good looking rifle.
Quality - very good for the price. My stock is a thing of beauty, IMHO. The walnut is a bit dark to begin with, so you have to spend some time thinking about finish choices. If you don't want to think, check the forum for various oil finishes (no stain).
The lock and trigger are adequate, not L&R stuff, but decent enough.
The only significant wood work my .50 GPR kit took was on the butt, getting the buttplate to fit with a smooth transition. It was not daunting... using hand tools I would say I spent about 5 hours on it, but I took my time. All the other inletting was 99%, only a bit of touch up on the tang and lock. Very very minor.
My barrel exterior, nose cap and butt plate needed filing and sanding to remove machining marks. That was probably the most tedious part. Again, I used hand tools only, files and sandpaper. I didn't keep track of the hours but I did it over a few weekends.
I used LMF to brown, it was rather fun, I think, learning the process. Again, there are numerous forum posts telling you how to do it. Small parts are a bit tougher to get right. Once you get a feel for it, its relatively smooth going.