Creating this as a place to offering up possible City-City routes for racing categories.
Obviously due to the number of cities available even just in the base game, let alone including DLC, there's nigh infinity routes that could be categorised, so any suggestion should be accompanied by an explanation for what makes that point-to-point special in some way.
e.g. Duisberg to Calais - apparently has some significance to those who are part of the Truckers MP community, and would likely be a new shortest run instead of Edinburgh-London. It's a minor road with twists and turns, and the ability to service-warp in RTA is complicated (until right near the end) due to the positioning of Brussels and Lille, which could mean some interesting experimentation.
Ideally for a new route to be added, it would be expected to see an initial run linked by someone - should not have to be the person making the original suggestion - so we don't just end up with a bunch of empty categories. Those initial runs could then be submitted once the category is created (or submitted on behalf by the mod adding the category).
Originally I was going to add the run as Aberdeen-Istanbul, and even did a run of that route, but the first half or so of the run was basically just the same as Aberdeen-Bratislava so it only got interesting after the first half.
Swapping it around to go the other direction made it more unique, and also increases the challenge by having the skinny back roads of Scotland be at the end, instead of the more easily resettable start.
That could be interesting - perhaps a Baltic capitals run? As in not just the Baltic states, but all the countries that border the sea, since Denmark and Sweden kind of make sense - Germany and Poland probably do not though.