I started writing a bunch of stuff, and then re-read your question and realised what i answered wasn't what you were asking, but i'll leave at the bottom regardless.
In the help for the transformer it links to a blog post written by @mark2atsafe that should give you some good examples
I'm no mathmatician, but from my point of view, a minimum spanning tree is similar to/a sub set of the traveling salesman problem
These problems can get incredibly complex and i'm sure someone on here will have a much better understanding than I do
In terms of a workbench, I don't have one, but i'd imagine you'd need to follow the logic of the Kruskal algortihm, below is a link/guide on implementing it in python