The iPad mini is great for portability, it basically fits into a large inside coat pocket, it's a bit of a compromise in terms of screen size for reading text on websites. If absolute portability isn't an issue then go full size.
I have an iPad1 - had it since shortly after launch - it's fantastic but feels a bit dated now as it's only iOS5 and it's noticably slower than newer models but I have no issues with the screen, yes next to a Retina it's noticable but stand alone the screen quality still amazes.
You don't need 3G (as you say) you can either use your phone to act as a router or use WiFi which is available in so many places and download a lot of content to read offline. If you really must you can get a mobile wifi device, I have one from 3 which works very well but it doesn't get that much use.
EDIT: have a play with both in an Apple store and get staff to show you as there a features you might not stumble accross, suggest you try reading some newspaper websites to see how you like text sizes (or load STW Forum) - zooming in is very easy with swipe gestures also you have the "reader" option in Safari which for someone with poor eyesite and who often forgets my reading glasses is handy. A mini will probably fit into a ladies handbag so might be a factor if it's a gift.