Welcome~! To sink right into it, RPC has it's own Wiki page which has a bounty of lore, as well as the ability to create your own 'character biography' so to speak. Making a wiki page specifically for your character that you can toss at people in game, or shove in your Signature.
There's a button right up on the hotbar which will send you to it, but for lazy man purposes, click ~Here!~
As for timeline wise, this link is a rather popular source, but it might not provide the depth you're looking for. ~Here!~
For some nice, detailed goodness, I'd turn to these forums, not only are there  multiple threads on certain concerns but there's also bulk lore threads, such as the Role-Play Handbook by Eva: ~Here!~
Hope these help!
Edit: I totally forgot about the last question. AHEM, yes it's rather easy. The Main 3 City States are connected via Airships. It costs 200 gil for a 1 way ticket to any city, from any city. But this feature is only unlocked after a certain point in the 'main' storyline. Around level 15.
There's a button right up on the hotbar which will send you to it, but for lazy man purposes, click ~Here!~
As for timeline wise, this link is a rather popular source, but it might not provide the depth you're looking for. ~Here!~
For some nice, detailed goodness, I'd turn to these forums, not only are there  multiple threads on certain concerns but there's also bulk lore threads, such as the Role-Play Handbook by Eva: ~Here!~
Hope these help!
Edit: I totally forgot about the last question. AHEM, yes it's rather easy. The Main 3 City States are connected via Airships. It costs 200 gil for a 1 way ticket to any city, from any city. But this feature is only unlocked after a certain point in the 'main' storyline. Around level 15.
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