I aspire to the same idea.
Having read some good essays on the internet, it seems the first thing you need is your stock blank cut / planed or whatever - to be nice and square all around. I thought of paying a joinery shop for doing that with their large tools (fnark).
Next is inletting the blank for the action. Having the factory stock & action to hand should make this possible. Remembering to drill the hole(s) for the stock fixing(s) while the blank is still square.
Then it's just the ten or so minutes whittling to turn the inletted plank into a stock!