What country would you guys bet the 5th route will be located in? Let's see if were right after NEC release...
It seems DTG is going on a constant cycle. Starting with the US, then the UK, then Germany. So I'd say UK is going to be next.
It'll definitely be a UK route, they're following the a pattern. It's also worth pointing out that DTG are probably building routes in TSW along their existing license agreements. It's a lot more cost effective to take an existing license for GWR, Amtrak and so on and to do a route based around that license than to get a new license.
I feel like this heavily depends on whether DTG will extend the current GWML in the near future ("march is looking busy on my calendar") and add rolling stock. Because if they do, I don't see it being important releasing a new UK route. Atleast I'd rather have them focusing on the GWML and making it really great, being it extended slowly but surely than to have them working on several UK routes which may or may not be extended, though they are [very keen to explore the possibilities of route extension].
DTG said it would take a while for them to make international (non-US/UK/DE) routes so until then they will probably continue with the current pattern and make a UK route next.
Maybe the main problem to go international for them could be licencing - which could be limited when doing a older time route. And languages to do researches. If DTG wants to do a french, a belgian or a maghrebian route, DTG will have to know french or french people who knows were to search (train mag, archive...). and secondly an old timer route could be welcome (steam)
Although I'm not literally gambling on it, my guess is that their next route for Train Sim World will be a British route since the cycle shows that it's American-British-German and then repeats. I also predict that their next British route will include a steam locomotive because the cycle has been American diesel, British diesel, German electric, then American electric and diesel.