Welll, I wouldn't plan a trip that involves extra plane tickets just to use 37 points--esp. with the $$$ of an European trip---but, you never know what will come up---either with you or your cousin or some other friend in the next 15 months--so, just hold on to them--or book the Mday trip--you can cancel, as you said, if something better comes up.
And, I really think that if you find that no one is going to plan to use them by next May or so, you can place a rental ad and just specify only
DVC members---many DVCers have already done their 1 transfer for the year and might need extra points---it could be me--LOL! I just used all of my 2010 points and already had a transfer---no trips planned right now, but many times, we are looking for just a studio or 1 Br for a night or so--I really think there are others like me and DVCers know the gig--so there's not really a lot of back and forth and not much risk of them trashing the place.
So, I would plan your European trip and let the 37 points take care of themselves. Elaine (DLP is on my list for the next Europe trip--whenever that is...)