So in a recent playthrough on medium setting I noticed someething with levelling combat experience.
As usual i went for the nearest Tiki Village with 2 huts, to eliminate the nearest threat so I have more time to prep. There were only 3 towns, 2 small ones medium / far away and a large one in the middle.
Anyway as soon as I had stone swords and appretice uniforms I sent my 3 guys up and they knocked everyone down, I managed to destroy a hut before everyone got hungry and I called a retreat.
Here comes the thing:
With the one hut one goblin re spawned, I sent out my single best fighter to fight / kill him and noticed while going there he would already gain experience. Guy was limping so it took far longer and he actually made a level in combat (150) without even yet killing the goblin. So I repeated this with all my 3 dudes and later on with any new guys and it was very easy to afterwards steamroll all the other villages.
It’s basically like combat training, except they gain the experience while walking around and it seems much faster than with the training puppet.
Edit - addendum - it’s even better not killing the goblin in the camp, but just leaving him unconscious, like that you don’t have to wait for respawn and can do the trip twice (after eating up etc.)