In addition to global roaming (at $25 for 100 MB of data, which I found manageable when I traveled through Europe last fall - I used 98 MB as I left
), you would also want to turn on the free international dialing option on your plan, so you can call local numbers while you are away from the US. The $25 plan can be turned on and off when you need it, though if you deactivate prior to the end of the month they also prorate the data plan - so, if you turn it on for two weeks, the data plan only covers 50 MB. I just turned off mobile data and used WiFi only except for those times when I wanted to use data - to look at Google maps, etc. But, yes, calling rates and text rates are high, too.
But if you do plan to use data and will be in one country for a decent period of time, buying a local SIM is easily your best bet. You can buy a pre-paid SIM with much lower voice and text rates and get a lot more data for the same price, with the price of getting a local number to the country that you are in, rather than your own Verizon number. (That was fine with me.)
There is a thread about this here, from a traveler to the UK (and another to Nepal), where I gave a link to a place that sells prepaid SIMs before your trip:
http://forums.androidcentral.com/motorola-droid-turbo/504705-these-phones-unocked.html