In the days my wife was an F/A for a UK charter airline with B707s (that tells you how long ago it was) they did indeed stay all week at such places as LAX and YVR. Those days are long gone and now crews will be positioned (either by scheduled flight or private charter) to fly the return leg from some other point served in the area - most probably the next day! Don't forget that these operators have a flight almost every day to some Caribbean island, Mexico or Florida (etc).