Exporting a complex model

#1 Can you split the bridge up into multiple sections and export each section?

Also and object that long might have trouble with LOD Splitting it up into multiple object would give you a better chance of getting the poly count down when someone is looking down the bridge from one end (my guess - never made and object that big.)

#2 You can manually enter the coordinates.

you need not rely on the editor..
merely get it close.
and manually adjust you will get it as tight as you need to.

Edit:

of course the trick is if you want it on fancy angles and such in the game..
you need only configure it straight without rotation
and add rotation as a group.
no problem.