I GMed Blacksmith, Mining and Swords all by doing smithy BODs for the Trinsic Jobs Board Smithy quest. The Training guy there offered for me to spend my points on those three skills. He should have made you the same offer. Go back and check it. I was able to spend the points gained from the quests on any of those three skills until I topped out each at 100. I know what you mean about not being able to do the same thing in Skara for Carpentry since it isn't an option. I was thinking the same thing as you are but then I went back to the Carpentry shop in Skara and spoke to one of the two NPCs there and was given another quest to turn in 25 Carpenter BODs. I think I had to do that 2-3 times but that is what you have to do to GM Carpentry. It is GMed as a reward for doing all the BODs. I was just going to GM Smithy and Mining but I also had to GM Swords to move on in the narrative. Do you have any unfinished quests in your log?