See http://www.theyeshivaworld.com/coffeeroom/topic/taking-vacation-holidays-between-dec-25-and-jan-1
On this issue, see Igros Moshe Y.D. vol 3, simon 85 that one should not vacation during this time EVEN if he has no intention to celebrate in their holidays, but vacations merely because the parents are off work and want to take a family trip, since the innocent intentions do not vitiate the issur.
See further, Netei Gavriel, addition to Hilchos Chanuka, Minhagei Nitel, ch. 4, halacha 14 and footnote 16 and 17.