I've had a look at the save, I'll try to play it tomorrow if no-one minds.
I think we should focus our builds more, we don't need things like Broadway. Heck, I wouldn't even have chosen Statue of Liberty. For the same amount of hammers, we could have had another dozen troops smashing through the enemy lines by now. So I'm thinking of stopping quite a lot of civilian builds in favour of military builds. We don't need many tech anyway, we'll want Industrialism, Combustion (boats & tanks), and perhaps artillery and flight+radio, but these aren't even necessary.
We need 18% of the land, and Spain has 15, so after Spain, we should probably let our marines hit France too.
I'll mostly be building marines when we've got Industrialism, as marines are strong (24 strength), and they can attack from the sea and across rivers, which speeds up our wars. Spain has got a lot of troops though, so I'll wait a bit for reinforcements. Airships should be helping us here, by hitting these City Garrison 2 longbows. Hopefully our cannons can take down their main stacks. I'll also try to railroad back from the north to Spain to move our troops quickly. We can move most of our troops back, as there is no major threat in that area.