Not really a bug, but this made me laugh (world gen)

Hmm, with cities like that, do you get like a... Super fast path or something? So you can travel about eight tiles in a single turn?

Yes. I've bitched about it extensively in other threads

I build my cities as long strings specifically to abuse that, it allows my armies to travel across a good chunk of the map near my cities much faster.

edit: Also it's not 8 for a max city, it's more like 13-14, more with careful placement.

Some one should invent some kind of wooden device that floats upon the water that a person could use to traverse the water and obtain the treasure.  

Sounds like magic to me

Actually, Master of Magic had such a spell - Floating Island

Failing that, some sort of structure to 'bridge' the gap between the two land masses, I would call it a 'structure between places' but I am sure there may be a simpler name for it.

Spell: Raise Land.