You could connect a PogoPlug device to your NAS, and you can access it anywhere in the world. The biggest problem is that if your network connection at home hangs/dies, then you cannot access it.
I second the Dropbox recommendation. 100GB is $100/yr. Move what files you think you'd possibly need onto it prior to traveling. The best part of Dropbox is that it can automagically upload all photos when you insert a media card into your laptop; or when your smartphone is connected to wifi.
1TB USB3 portable drives are getting pretty inexpensive, too.