C
While waiting for an update, you can always create a mod to run your own scenarios on, but note that scenarios utilizing your mod would probably not work on the updated versions when and if that ever arrives as it's a different route, technically. I know that some DTG routes have had scenery reworks from users and are on the Steam workshop available for download, often as separate routes. One even gives instructions on optionally moving the assets to the main route folder to apply it to the original route, though this could be inadvertently removed if an update is ever generated (like the annual updates) and thus it would need to be done annually or the applicable folders backed up to restore right away.
