Pete thanks for sharing your game with us.
I gave it a try and used a more aggressive openning:
Tech order: BW-Fishing-Hunting-AH-Wheel-Potery-Writing-Alphabet-Iron working-Math-Construction-Mono-COL-Civil Service
Build order: Worker-Worker(chopped)-FB(chopped)-FB(chopped)-Worrior-Settler(chopped)
The reason for this order is because the seafood tiles give you by far the most net output (Fish=5F+3C=8 net, crab=7 net), you want to work them ASAP and you get a boost in food and science. Hence my order. 2 workers are necessary for chopping, mining and etc. I even mined pig hill before i got AH to get 2F+3H.
the first pop works Fish, as soon as the 2nd pop arrive, he works crab. 3rd pop works mined pig hill, later pastured pig hill. You should always ask "what would be the best tile for my next pop to work on given the available tech", and the answer to this question should guild your worker actions. So having 2 workers early is huge because you can work the horse 2 turns faster and 4 turns faster to work both Pig and horse (faster growth and building settler) than a single worker start.
Give this openning a try, compare to your current start, you might be surprised how powerful you grow by 1500BC.
Dont ever think "save the trees before Math", chop them whenever you need most, and that is always the early the better. Early advantages grow exponentially in this game. Besides you need to clear those riverside Grasslands for cottages

. In this game, chop the hill trees(Seoul) first follow by mines, pre-wheel, this saves turns. I chopped 4 trees early, had 2 trees grown, saved 4 for later, most likely the GL.
When i got Alphabet(around 1500BC), The AIs had almost nothing valuable to trade to me, i had to research most key techs myself: Iron working-Math-Construction-COL-Civil Service. But most these techs took 6 turns or less. I set 2 scientists in captial as soon as i built liberary. Used the GS on an academy. This academy almost trimmed all subsequent research by 1 turn per tech.
I converted to Roosvelt's religion as soon as it spreads to Seoul because i need the happiness bonus, also soon switched to Organized religion for prod boost. And i know i will capture his holy city very soon.
On the war front, try take out Roosvelt ASAP as he is closest to you, you will gain his cities with a lot less maintainence costs than Cathy's. Also he has marble which to me is always top priority as you need it for GL, NE and HE ASAP.
I got open border with them early and sent out 1 chariot each to explore their lands before planning the attack.
Roosvelt does not have metal early so all you need is CR swordsman and Hewacha. I build units from all my 3 cities and soon had a force of 8 swords and 5 hewacha. Pretty much rolled over Roosevelt and took Washington by 25AD. Got 1 GG duing this war from killing hordes of his archers, and settled the GG in Seoul as instructor. Got bunch of CRIII and CRII swords and Hewach veterans as well and they are ready for Cathy.
Think I might finish this game this weekend. Great game so far.