We should have that city settled by t110 at the latest, by my reckoning, and that includes expanding for the two eastern city sites. Definately worth it, as NE city (even with all of the forests chopped to speed growth, there are 13 forests, so with maths that is enough hammers for granary, forge, lib and NE, with 2 spare due to forge bonus). It can support 7 specialists at size 11 (with CS and calendar, which we should have by the time it scales those heady heights). It's definately a city site that we should push for.
Looking at the numbers, it shouldn't cost us more than 7, 8 at the most GNP after city 5 is settled, if we were to keep it. Grr. I'd say if we were to capture a worker, it'd be worth it from a domestic PoV, because it would only cost us about 6gpt, because it could road to the river, but it would really screw with scouting for Saturn, because Barentz would have to be assigned to defense duty, which we cannot afford at any cost, really. Getting another unit down there would take 10 turns at the least.
Probably for the best to just raze it and use the gold to fund deficit research, even if we were to find a worker. If the worker were to find it's way to CK, awesome, if not, no biggie, not like they are overly expensive to us...(If you hadn't noticed, I'd like to keep the city...although the city site signalled is just so much more awesome, it takes 25 turns max to hit size 11 using just the tiles we can see).