Along with dropping curves onto mesh surfaces and duplicating objects along curves this makes for some very interesting tools.
For this coat I used Slice by Mesh to neatly cut an opening out of a Mesh.

Then I used Extract Mesh Boundary to turn the edge into a Curve to reuse in different ways. I think the Extruded Slab would work well too if you need a square edge.

You don't have to actually cut the mesh to extract curves, any masked selection will work too.
Here are a couple of examples of adding a border to a shape. These are Slabs (drawn shapes) extruded and oriented to a pair of curves (the rails) one on the boundary and one inset a little bit using the "Slice Near Curve" action.
These should turn out with good UVs ready to add a texture or bumpmap along the border to add extra detail.
