If you do go the local SIM route, you could set up Google Voice and make calls to the US that way. It can even be set up so that you can answer calls without having to go into the Hangouts app (the normal incoming call screen will appear with "Hangouts Audio" on it and the calls will appear in the native call history too). I'm not exactly sure how much data such a call uses, however, so I'd make sure to purchase a fair bit of data just in case.