obirek - I would not recommend stages 1 and 2 that you have given without alterations. For a start, it's UserData/original and UserData/local that need to be backed up, and Trainz does have it's own uninstaller (if it doesn't work for some reason it's better to use a third-party utility like Revo Uninstaller to remove all the components, especially as Trainz has more than just files.
Also, with stage 4, it's better to use File > Import Content in Content Manager.
Shane