I would apreciate knowing when to use 'off' in sentences like ' He works off Alexandria'
We would say 'he works outside Alexandria', or 'he works near to Alexandria' or 'he works some way from Alexandria.
The use of 'off' comes in other meanings:
I will be setting off in a minute.
I will drop off those materials tomorrow.
Off you go (telling someone to go somewhere).
The player was off-side (as opposed to on-side).
The teacher gave him a good telling off.