My personal feeling is she may have a hard time typing on an iPad 2. I don't know how old your grandmother is, but my mother struggles with the touch screen typing on her iPhone. I have attempted, on a couple of occasions, to introduce her to the iPad, to see if it would be something that would interest her, but with no luck. She just can't master the touch screen typing, resizing, gestures, etc. She plods along one letter at a time, with the help of a stylus, the rare times she tries to type on the phone.
Something that is "the simplest" for you and I, may not be the simplest for your grandmother to use. My mother prefers her MBP and iMac, and your grandmother may prefer something along the lines of the HP i3. Talk to her a little and try to gauge her feelings about a tablet.
It is an awesome gift to give her, but by the same token, you don't wan't it to be something that may be frustrating for her as well. I know my mother would just get frustrated, and not use it.
You know your grandmother better than any of us do.