Great to see that army build up.
I'd move troops to 'the front' immediately - consolidate them in Steel Jaw Guy. We don't want to delay our invasion due to our troops loitering in far-away cities.
Also encouraging to see a bit of whipping and chopping in Steel Jaw Guy and Monte Carlo ... we need to keep going with it.
I'd work the food tiles more in Prague and Vienna. I'm a big fan of maturing Cottages, but the invasion force is the priority now, so Prague could go back to the Cows and Clams. One or two more rounds of whips and we'll be good to strike I suggest - and that's where we can turn our focus again to science - but with so much cash in the bank we can certainly get back to a more balanced approach (see below re. suggestion on tech').
One turn of moving the citizen off the Vienna Gold Mine and onto the riverside Farmed Grassland will get that population up quicker.
We have a Warrior near Monte Carlo in a forest that can make his way across to Bibracte for city garrison duties. The city requires a thematic 're-name'! For now I'd Farm that other Floodplains for better whip-regrow. I'm also wondering if it wouldn't be better to take that Worker who's on the Bibracte Stone and complete the road network between the core empire and Bibracte instead (that is continuing diagonally across the Floodplains) so our units can move more quickly to 'the front'. I'm not sure if we really require Stone for anything too immediately (I assume we're not going for The Hanging Gardens, and the tile yield isn't as good as 'say' that riverside Plains Hill getting a Mine anyway).
I'd use the Chariot sitting on Vienna's Gold Mine to do some recon' on China. Just for the record - Guangzhou was the city that landed The Parthenon (you can zoom in and see it). It'd be nice to see what's sitting in Shanghai (3 Archers? 5 Archers + Axe? 5 Archers + Axe + Spear?).
That Prague Worker building a Farm on the riverside Plains could arguably build a Cottage there instead (in light of the city's considerable food haul) - Plains Farms are typically very ordinary tiles until Biology. That tile can't chain-irrigate to anywhere once we get Civil Service either. Better yet, get the Worker to chop that last Forest in Prague's BFC.
Thoughts on science? I was considering the value of going up the 'artistic' line toward Literature. We've got a bit of leeway in terms of happiness due to Charismatic + Stonehenge + 3 x happy resources, so arguably don't need to bee-line Monarchy / Hereditary Rule. Seeing Bismark's reluctant to trade Alphabet, I guess there's a case that we should self-research it.
Good stuff - over to FiveRings for a PPP!