+1 for stating what your wants/needs are for this thing on the road.

Apple= most expensive, but perhaps the easiest due to the fact that the UI is the same across all devices running the same OS version- whether it be the iPhone, iPod Touch, or iPad.

Android= hardware and pricing varies greatly; UI will vary as well- Samsung, Toshiba, HP... take the Android OS and then layer their own stuff on top. You get what you pay for when it comes to the Android devices, so best do your homework.

Windows= Not too many offerings running this and there are two different OS's that have subtle differences- Windows 8 and Windows 8 RT. If you go this route (and can afford it) Surface Pro with the W8 (non RT).

As you're not tech savvy, I'm not even gonna mention Ubuntu