Goin' off the rails
1918 A.D.: The remainder of the Danish navy is chased down and destroyed by UNK submersibles. With the besieging companies at Viborg holding strong, newly-arrived reinforcements are redirected to Aarhus.
1920 A.D.: A new UNK prime minister, as his first act in office, orchestrates a diplomatic pact between the UNK and both of the great Eastern powers: Rome and Russia, once bitter enemies.
With the Celts proving a notable exception, I've come to the conclusion that you just have to sail the way the diplomatic winds are blowing in Civ V. Denmark will soon be mine, which will mean I will share an enormous border with Greece. I saw a chance to unite Rome and Russia against them, and you can bet I took it. As of now, Russia is still friends with Greece (in addition to myself and Rome), so their loyalty isn't assured. I've also risked losing Spain as an ally. While not openly at war with Rome -- for the moment -- they are not exactly the best of friends.
The first major railroad in the UNK begins construction from Sigtuna to Stockholm, speeding commerce and creating thousands of new jobs.
Connecting cities with railroads gives both ends a nice production bonus, and it gives my workers (who were running out of tiles to improve) something to do. Where to set my tech path next, though? Plastics? Combustion engines? Oh, that's right. How about Nuclear Freaking Bombs? I'll pick up Replaceable Parts on the way, allowing the building of Great War Infantry and making my Caroleans obsolete. I'm going to focus all of my major cities on making as many Caroleans as possible in the nine turns before that happens, as any Caroleans that I upgrade to higher-tech infantry will retain their unique unit bonuses.
1921 A.D.: Rome and the UNK sign a research agreement. Something about cutting very tiny things in half. The majority of the world doesn't really understand the significance.
Greece capturing Vienna is really what re-asserted them as public enemy number one. I'm willing to say "No hard feelings" to Rome, so long as they can be useful.
Elsewhere, England and Denmark denounce the UNK's Celtic allies. It does them little good, as Aarhus is captured after a long and bloody siege. Viborg, amazingly, still holds out.