Darren --
I moved a business once -- from a 5th floor location in New York City....
We had the "new" location all mapped out - and all the electrical - phones etc and "mods" done in the new location completely finished BEFORE we even packed a single box.
We closed the books out at the end of the month.... Notice was sent to every customer in their statements and if no statement they were mailed one anyway. Then each person had a supply of boxes and tape - They were responsible for packing and labeling their area of influence/desk/operation.
The movers came in - trucked it to the new location - not far away - and each person was responsible for being there on Saturday, and Sunday if required - to unpack and get their area ready for Monday AM opening.
The move went off without a hitch.
The lender required inventory audit we had each year was far more disruptive!