The thing is, the German Army (V-2/A4 was Heer/Army development and operation, as opposed to the Luftwaffe's V-1) wasn't completely crazy and following Crossbow switched to small, easier deployed mobile launch sites - basically the precursor of current-day TELs.
Just need the Transporter/Erector, fuel bowser, control truck and a relatively small crew. In and out in about 2 hours total.
see http://www.v2platform.nl/book/loosduinen.html for more infrastructure and layout specifics.
(I must check my library again, as I believe Most Secret War by R.V. Jones has a picture of such a mobile site in the middle of a crossroad in The Hague...)
Operational use did not start until the first week of September 1944.
There were several elements of Batterie 444 active in the Netherlands, most famously in Wassenaar/The Hague, Hook of Holland, and surrounding areas, but also (and less used - about 20% of launches later in the war) in the Eastern parts of the country beyond Zwolle targeting the Southern targets like Antwerp.