Well, this was a standard pangea keshik konquest.
For the non-pangea part, here are some tricks I used:
- Hagai Sofia scientist bulbs astronomy.
- Fleet of captured workers explores the sea.
- Capture the smallest city as a beachhead, so there are less turns of resistance until I can annex and purchase more keshiks. (I actually sent over a settler to start purchasing faster, but all the city sites were taken.)
- Gift the smaller Russian city I captured to Askia, then sell him Moscow for 100gpt because it is a capital adjacent to his territory.