I would use wall tracing depending on which way the path turns and lerp (linear interpolate) that with the distance to the node. From far away the entity would travel straight for the node, as it approaches the node it would get closer to the wall, and right next to the node the entity would hug the wall. Then reverse this for going away and midway to the next node do it again. You can do wall tracing by c_tracing 90 or -90 degrees relative to the motion of the entity, if you have a lot of entities you will want to only trace a few frames per second and record the value because c_trace is slow.

edit: Multiply the amount the entity goes towards the wall by the sin of the angle of the turn capped to 90 degrees. And thank you for this contribution!