My own route is over 150-plus miles long, but I don't usually run over the whole length myself. I have AI drivers setup to run the length of the route. As they run along, they interact with my own running which is done around a local freight operation or commuter trains. My commuter trains, for example run either in loops or on an out and back from a station. With the AI-controlled commuter trains doing one thing along with the long AI-controlled freights, I busy myself with other operations myself. Other than the long distance passenger trains or long run-through freights, none of the trains run for more than 1 hour schedules max. I have plenty to do keeping everyone operating the way they should. Occasionally I will take over one of the long distance running trains for something different and this can be a few hours' journey to the other side of my map.
Now one of the things with a large map, is you need a purpose. My route is based on a theme which I setup many years ago and over time I have kept pretty consistent. This part in its self is quite a challenge because as we build a large route. Over time I have abandoned routes, added track in, revised track, and even chopped baseboards that I felt didn't add to the purpose. With abandoned lines, I will leave portions of them where they cross mainlines or branch off towards where they used to go. I will downgrade the track to rusty rails, put trees in the trackbed, and rip up junctions in places to make the area look like there was once a branch line or mainline that once ran in the area.
The benefits of running a long distance route in Trainz is truly one of the greatest things with this hobby. We don't have to worry about maintenance on such a large route. In a real model, for example we would be constantly cleaning and maintaining the route which can take more time than just using the trains. We also don't have the space issue which has always been a concern for real models.
Trainz User ID: 124863
TS12 Build: 61388
T:ANE Build: 81324