My single focus is the N.Park. I got Biology turn 93, 550BC. I did not take Astronomy first like I previously did. I just stayed completely focused on Bio.
Since I was in the West this time (with gold/silver/silver). I didn't have enough food to bother with Pyramids. (i.e. why waste all those hammers if you're only going to run 1 scientist + the 2 from G.Library)
I should have gone straight to constitution (for Rep) after Bio, but I forgot and did the usual Medicine (for Envir) and Astronomy.
Next, I go straight for Labs (superconductors).
Then I turned my focus to building/hammers (and go for Steel/Steam, etc)
That was another mistake: since I had Refrigeration, I should have gone to Econ+guild/bank/Corporation and incorporated Cereal Mills. That can give 5-10 food easily on this map. I did it eventually, but I delayed it a bit by turning my focus to hammers too early.