Some of the best layouts I have seen have been freelanced.
A friend of my dad who is a master modeler freelanced a fictional "Star Valley Lines" in the pines of north central Arizona.
He scratch built most of the rolling stock and did some fabulous kit bashes like converting a Bachmann run of the mill 10 wheeler into a duplex with the second drivers under the tender. Playful yet meticulously executed down to tools on the running boards.