I kit-bashed two Plasticville Union Stations into one long one, cut the result lengthwise, and mounted the Plasticville section to the back of a Lionel Grand Central Station - notably plain, and (dare I say) ugly. The Plasticville building(s) are mounted to a painted styrene piece that covers the back of the Lionel Station, and the styrene is attached using doublefaced tape. So the "collectible" is not ruined. Then, I glued a printed station interior to the styrene background, and lit the interior using 9 LED's. I added a second (incandescent) lamp to the Lionel GCS lighting.
The result (what I see) is a station that is more "grand" and impressive than either structure by itself.
My grandaughter (8 tears old) matched the paint for the Plasticville parts to the Lionel- pretty well, I think!!