Spent some time of my own with Adventure Mode, a couple thoughts on skilling up a warrior. I had good success starting with some points in Wrestling and Shield User and the rest in a weapon skill, I did Spear but ended up going from Dabbling to (finally) Legendary in Swordsman.
On your first couple quests, strangle everything. [shift]+[A] and wrestling an opponent, grabbing a head or limb and do a couple take downs. Then grab the throat, put in a chokehold and strangle until dead. Use another throw / take down if they try standing back up. This kept me relatively safe ... Until I got the hang of ruins. Smashing all the Skellies and Zombies, leave one Zed alive and just strangle and strangle him. Legendary Wrestler comes up pretty quick, just take a few steps back and "walk it off" when you get Tired.
This led me to realize how to get from Skilled Shield User and Armor User to Legendary in about 10 minutes. Visiting a ruin, I selectively culled the undead until about 3-4 Skeletons were left alive and intact. Using [c]ombat preferences attack was set to Close Combat (to prevent deadly counterstrikes) and the other two to Stand Ground. Then just lie on the ground and use the [.] rest key and roll with the punches. When you get tired, stand up, retreat and walk it off. Laying on the ground is important because it is only when you "block the shot" that shield user is trained and Skellies just miss if you are on your feet. I don't know how tough you have to be before this is safe, but test it with one Skeleton, or better one Zombie until you think you are safe.With max shield skill, I could ransack a Kobold cave and block down arrows with impunity.