Its possible to settle Green X and have a city on the north coast.
That solution is neat, but I see that our City 2 has more than a 4% per turn chance of Revolting, and that's with each of:
1. Churchill not having a Holy City, which he might, such that his Cultural pressure would be even worse than in the test game
AND
2. Using the Missionary in that second City
AND
3. Detouring to Mysticism early and building an early Monument in that City
I.e. That's with us already doing everything that we can to keep that City and it's still in serious danger of randomly being lost to Churchill.
GLH is killer in BtS.... If Churchill is on an island then GLH means we have our strategy: kill Churchill, get Stonehenge, build GLH.... profit.
I went to set up this situation in our test game, with there being an immediate jump in Trade Route income by making Churchill's area an island.
It is true that overseas, foreign Trade Routes are strong, and it is also true, as you have implied, that overseas, domestic Trade Routes are strong (and can be re-used amongst each of our Cities, unlike foreign ones, which can only be used by 1 of our Cities at a maximum). Obviously, by capturing Churchill's Cities, the Trade Routes would become overseas, domestic Trade Routes.
Yet, when Churchill's land becomes an island, the normal "Culture can't spread outside of a big fat cross beyond two squares over water" rule comes into play. Having played several Culture-flipping games, it has been bugging me at the back of my mind why we were getting swamped by Churchill's overseas City's Culture (Culture spreads overseas in Vanilla and Warlords, but gets cut off in BtS), although I'd been thinking of London as being overseas when targeting The Great Lighthouse--France vs England made for a nice little amphibious assault in a multiplayer Civ 4 Earth Map game that I played, building The Great Lighthouse by settling Paris on the water and then amphibiously assaulting and capturing London with 4 Axemen hidden on Galleys in a surprise war declaration. Yet, London is not overseas here and hence the Vanilla-like Culture effect.
So, therefore, we have two possible situations:
1. Churchill is not on an island, and there might not, in fact, be any islands in the game, meaning that there are no overseas Trade Routes, which diminishes the value of The Great Lighthouse significantly
OR
2. Churchill is on an island, in which case there will be 40 Culture per turn going into the Fish after London hits 500 Culture, but there will be 0 Culture per turn going into the Cow
We have not been playing toward either possibility properly, as we have been playing with the impression that we'll get great overseas, foreign Trade Routes from England but will also have to fight Churchill's Culture for the Cow. Yet, we can only have one of these situations. So, perhaps it is a bit foolhardy to mix these two possibilities together.
Either The Great Lighthouse will be awesome but we won't have to fight for the Cow, or we'll have to fight for the Cow, but The Great Lighthouse will be mediocre.
Thus, perhaps the discussion should shift to deciding whether or not to settle adjacent to the Fish.
We know for sure that the Fish will be in danger by Churchill's Culture, so one option is to focus on settling adjacent to the Fish, securing us a Resource that other teams might not get unless they do the same thing.
The big risk, here, though, is that Churchill is not overseas, meaning that we'd lose the Cow, would have a 1-Food-Resource capital for a long time, would be on the Coast in a game where The Great Lighthouse isn't amazing, and would have to tech Fishing in a game where The Great Lighthouse isn't amazing (i.e. we'd need Fishing for our lone Food source, but then we'd mess up an Engineering Lightbulb).
Or, we could luck out and have a capital with Fish + Cow + Fur all being workable in a game where The Great Lighthouse + capturing Churchill's City or two will make for all of our Cities having 1 or 2 overseas Trade Routes. The biggest challenge that I see is "how will we get enough production (except via Whipping) in order to build The Great Lighthouse?" I don't have a great answer to that question other than actually getting that production via Whipping, which would entail delaying Alphabet by teching Fishing, Animal Husbandry, Pottery, Mining, Bronze Working, Sailing, Masonry (maybe Mysticism before it), Writing, and only then Alphabet, which is no longer an Alphabet beeline. We don't have to beeline Alphabet if going for the other techs makes sense to go for. But, it will suck if we lose the Cow to Churchill, and the annoying part is that we don't get to work the Deer, so our Worker takes 15 turns to build and there is a risk that his only really useful job for a while will be to Camp the Fur.
Another option could be to stick with the Wheat and the Deer, but play the odds and settle 1 N.
If Churchill is on our landmass, we can plan to Axe/Sword rush him in order to give us our Cow, as we'll know that he's on our landmass when he steals the Cow from us. We can also stick with an Engineering beeline approach.
If Churchill is not on our landmass, we'll have the Cow within our big fat cross and we can settle our second City where pigswill placed it in his latest test game, getting to use the Cow in City 2 without needing a Monument or Christianity in City 2, but also getting to improve several GH squares and Chop several Forests for The Great Lighthouse being built in City 2. We wouldn't benefit from the extra Trade Routes in our capital, but our capital would be taking the Cottage-heavy approach, instead.
Either way, we'd get Deer, Wheat, Fur, and 1 GH square, and we'd get our 12-turn Worker, while still keeping our options open (having a good spot for The Great Lighthouse for City 2 or forgetting about Fishing and going for Engineering).
We'd also then be able to afford to explore more with our Missionary, at least until Turn 5 when Barb Animals will start to appear (I don't want to see him getting eaten by a two-move Wolf that we might not see, which can appear on any unspawnbusted Forested square).