Map out progression rewards for achieving internal goals, how much stonecrafting XP is there to get, plot an S-curve, doing stonecrafting tasks moves you along the X axis and resulting skill bennies on the Y. Pass the big-payoff part of the curve you hit diminishing returns, your 50th stone tool of any sort gets you not very much because there's not much more stonecrafting XP left to get. How much normal-zed/feral-zed/rad-zed POI-clearing XP is there to get? S-curve progression. Probably getting too cute with it, your progression could be multidimensional, so you have a club curve and a shovel curve and a stone curve and an iron curve -- you could even get _really_ ♥♥♥♥ing cute and factor the party use progression into the crafting skill, so if nobody in your party ever uses a bow that's near your currrent competence level you can make all the bows you want, but you'll never get better because you've got no clue what works.