Here are a few of my tips, in addition to the good responses above.
Avoid the #swishbang of the sliding door, from the outside, close to the catch point then use your palm to do the final latch. From the inside fit a glass carrier to the inside glass and use it to pull close at night, then let the power latch complete the close.
Try to educate the family to close the doors quietly, (some vehicles have 20 doors by the sound of it)
Don't use the key fob to lock the door, use the button on the driver's door. Late-night alarms are very annoying and just tell everyone you don't know what you are doing.
Turn headlight switch from AUTO to off as soon as you arrive, Floodlighting the campers opposite when you get back from the pub is not appreciated.
Sort out your van and put away stuff you don't want knicked before you get legless and fall into bed!
Put your chairs under the van at night unless you want wet seats to sit on at breakfast.