I did take the save from the end of Sirians turn and play the game out.
Highlights in case anyone is interested...
Fought the war with America and did take the "thumb" cities they had stuck up into our turf. I also took two Las Vegas and Richmond because they had thick jungles on their other sides, where I could pillage the roads and slow down the American attack. Other than that I turtled to wait out the storm.
France and America made peace with about 10 turns left in our alliance but Korea and America fought until about 4 turns left, when they made peace. I attacked the American troops in our territory, killing as many of them as possible (they had swarmed over the boarders when peace with France was made) and my last attack was with the War Elephant, thus saving the GA for peace time.
No wars for the rest of the game for us, and the AI's were humming right along, staying 2-4 techs ahead until America declared war on Korea about 1700, and they stayed at war for a long, long time. Korea changed from Democracy to Monarchy because they bombarded the American coas the entire time.
Korea and America finally established peace just long enough for America to get Motorized Transport, Radio and Flight and then they declared war on the French. Abe swallowed about 5 cities in 5 turns right off the bat (he had a large army from fighting to take the Korean cities earlier) so I traded Joanie Oil, Rubber, Iron and Aluminum so she could build tanks and other defensive stuff.
With over 37k in the bank I kept 4 turn research going the entire time. Korea made it into the modern age first and got Rocketry, the bogged down drastically and never got more than 2 more tech's in the Modern age by the time our Spaceship was complete. Abe and Joanie stabilized in their war with about 1/3 of France gone, and neither ever researched more than 2 tech's in the Modern age that I could tell, although both had Computers, but not Synthetic Fibers.
Spaceship launched in 1870 AD, about 4 turns later than it should have but I waited until the trade deal with Joanie expired. All the modern tech's necessary for space had been discovered with the addition of Smart Weapons on the way to building the SDI defense thing. Final score of 6400-6500.
Oh, and I gave Abe a parting gift of three ICBM's to his top three cities of Washington, New York and San Francisco on the turn before the last two cities finished the ship.

Heh, I had our entire border staffed with MI 3 deep (on one square), stacked with fortifications and about 5 artillery for each position. He broke through the line but would have been pulverized on my next turn because I had build 100 artillery, we still had all the Cavalry, and a handful of tanks and Modern Armor.
Fun game, but after it was clear the AI wars were killing their science it just became a waiting game.