Hi Mike,
Breskens on the Westerschelde estuary - nice - and an easy drive into Belgium for some beer. We have business partners and clients in Middelburg, just across the estuary (by ferry for foot and bike passengers) or the Westerschelde toltunnel for cars.
What sort of map do you want? A detailed road map or something with topographical features for walking? Both Topografische Dienst (Dutch OS maps) and ANWB (Dutch AA) do 1:50000 maps of Holland.
In the UK, I'd recommend "Stanfords" in London http://www.stanfords.co.uk/ as the primary retailer of paper maps in the UK
Otherwise, you should be able to pick up a 1:50k map in any Dutch town centre - or order direct from ANWB in Holland
Enjoy your time in Holland, Robert