Sailing->Mathematics->Calender->Bronze Working->Metal Casting->Iron Working...
I've been starting out something like (as best I can remember -- I'm still on vacation, and don't have the game in front of me):
Bronze Working->Sailing->Mathematics->Calendar->Archery->Iron Working->Monarchy->Currency...
The earlier Bronze Working lets you chop slightly sooner around Tuitan (although I wait until I've got Mathematics to complete the chop, so as to get the most benefit from it). You still have time to get Calendar before the deadline, even if you research Bronze Working first.
I think you need either Currency or Alphabet to get to Optics in time (unless you're unusually lucky and get a tech that leads to Optics from a hut). Alphabet lets you build Research directly, but I prefer Currency: not only can you build Wealth (which lets you keep the research slider at a higher setting, giving you much the same effect as building Research), but you can also build Markets early on.
I'd use the Great Scientists for Academies rather than bulbing anything, at least early on. Alphabet is pretty quick to research, and anyway, you'll find someone to trade it to you once you cross the ocean. On the other hand, the benefits of Academies will start immediately and last throughout the game, and I assume you'll need all the research bonuses you can get to complete the tech tree first.
I usually experience my first barb attacks right after getting Calendar, so I research Archery and get some better defenders than the initial Warriors. I use the Archers for some impossible-odds attacks against the barbs, as long as I still have the free barb attacks; this gets some heavily-promoted units early on that can be turned into Crossbows later. (You could use the Warriors, too, but it will be longer before you can upgrade them to something that's really invulnerable to barbs and Natives, so I figure the promotions are better applied to Archers. I don't usually build or upgrade to Holkans at all, because their stats aren't good enough to be guaranteed a win against the riffraff. It's better to have a small military of strong units than a large military of weak units, to avoid paying military maintenance.)
As soon as I have Iron Working, I build a mine on the jungle hill southeast of Oaxaca, giving it some much-needed hammers. This is also around the time when I found Chicago, so I want to mine the iron there as quickly as possible.
When I get Monarchy I switch to Slavery and Hereditary Rule.
After that, I beeline Machinery (Crossbows and Windmills), then Optics. I've been getting Optics around 1260, which is early enough if you have a Trireme already built and ready to upgrade to a Caravel sitting off the Yucatan.
After contact, I go for Astronomy first, so as to be able to start transoceanic trade as early as possible.
I've never successfully gotten much past the discovery of Astronomy, so take all my advice with a grain of salt. I hope to try again in a couple of weeks...