When I travel abroad the first thing that goes in the suitcase is an old fashion hot water bottle. takes little room and very handy for both hot and cold water!
Also I invest in one of those silver Emergency Blankets - pretty cheap- they're silver and fold into a tiny packet. If the matress is cold, just unfold and put it under you. Promlem solved. Takes less room than a pack of cigarettes (remember them?) The blanket will also reflect heat if you are in torrid climes. Oh, and talk to your bank NOW ... if arranged ahead you can buy some traveller checks in Irish Punts or Euros which are taken everywhere and there is no charge for changing from US dollars. When I was there Jury's hotel wanted 30 percent to change dollars to punts on a Sunday checkout! So I stayed another night and went to the bank next day and changed them and came out even!
If you can find them : I used Kennedy half dollars as little souvenirs for children I met on the way. They loved them.
Another big hit was a Polaroid camera so I could give pictures to people on the spot
