I tried making a post like this before, but it appears to have disappeared. This forum is buggy.
In the first cave, I stand on the bridge and I click on the first artifact and the PC goes right there. I click a little to the side nothing. I also have experience with houses. I’m not sure how you implement the pathfinding but one technique involves invisible “rails”. If you can draw an unobscured line from a rail to a point, you should be able to get to that point.