1. If I have a city with very large cultural borders, is there any point in building farms, workshops or cottages on tiles that are out of its working range (aside from, of course, building another city with those tiles within its range)? What is a good use for them?
Apart from hooking up special resources, and forts for defense (or as channels or airbases), there's no use building improvements in tiles that your cities can't work.
2. This is going to sound like a very stupid question - if I build several cities does it slow down their
growth? In my first game my cities' cultures didn't grow much but in my last game, for fun I tried to see if I could win having one massive city. Its culture was ridiculously high. I was playing on the quickest speed and it reached Legendary ages before the end.
Each city has its own cultural growth, they don't influence each other. Hover your mouse over the purple culture bar (city screen, lower left) to see a city's cultural growth. Wonders usually produce a lot of culture - if you had only one city, and concentrated wonders there, then the city certainly had more cultural growth as when you spread the wonders across several cities. Also, you may have used great artists differently.
3. If you have bunch of workers hovering around a city, do you automate them all? I did that in my last game but I'm starting to think their AI for building improvements is awful - my city needed extra
and there was a rice field nearby, but the worker there thought it was a good idea to build a fort there.
That's actually a good idea since the fort does hook up the resource. If the rice field wasn't workable for your city, then building a fort is better than building a farm, because the fort can also be used as a channel, airbase, or defense position. It takes longer to build though.
In general, it is better to manage workers manually though. The AI does not take specific needs of a city into account (though I think the Better AI mod changed that), and is too eager to destroy existng improvements if you allow it (there's a game option "auto workers leave existing improvements intact"). But the workers are not so stupid that they build improvements in places where they make no sense at all (as you may have thought when you saw them building the fort).
4. One thing that irritates me a little is that you can only view the civ / leader bonuses when starting a game in Play Now, or Quick Play, can't remember what it's called, but custom game has far more options (I'd rather disable timed victory and specify exactly how many other civs I want in the game)...however in custom game I can't view the bonuses or how my leader looks when selecting leader and civ. Is there a mod so I can view the bonuses while selecting my civ / leader in custom game or is it just something you learn through experience?
Hmm, never missed that info. Doesn't the manual escribe the bonuses? Or could you check the Civilopedia before entering the "Custom game" screen? There's also a very good PDF companion for BtS floating around on the forums, which (IIRC) has the information you want, and neatly ordered too.
5. What settings (difficulty / map type / size / number of other civs) should I first go with to learn the game? I don't want something too easy, but I've lost both of my games so far (one on warlord, the other using just one city)
Hard to give general advice here, as every player is different. If you lost two Warlords games, I'd play one on Settler and see which level I enjoyed more. The game is quite complex and even a veteran can still discover new things, so a player's first games will never be "optimal". Just choose a level that provides an enjoyable experience for you while you learn the game, and experiment a bit.
Edit: And now we're double-crossed. Waiting for the XXX post to come in any moment.
You can even tell your vassal which tech to research, so if he has a decent research rate, it's sometimes useful to give him techs so that the two of you can both research important techs, then trade them among each other when you get them.
