I like to travel through south east asia, and usually go every other year if not every year. Cellphone coverage over there is great! I have a very simple phone I bought in singapore, that I take with me. As soon as I get off the plane in whatever country I am in I buy a simcard, plug it in and call home to let them know my number for the next X days. Cellphone coverage in most of SE Asia seems to be better than the US, not sure if a similar situation would work in Europe.