I have some of the 29x2.35s (about 60mm wide!) on a Surly Karate Monkee, as a fun bike. The Big Apples are for summer, and Continental Top Contact Winters go on for the colder months.
FWIW, I'm right at the clyde boundary, and those monster Big Apples let me float over all sorts of irregular surfaces that are out of bounds on my road bike. They only get pumped up to 50psi, or so, and there is little I can't comfortably roll over. Very lightweight, and compliant, for their size. That said, they have way more rolling resistance than the 700x32s Vittoria Ranodneur Hypers (Vittoria now call these 'Voyager Hypers', you want the 120tpi casing) I run on my normal commuter rig.
How long is the commute? If more than a few miles, I wouldn't suggest the Big Apples, unless the terrain in broken/gravel/etc. or you think she needs to work a little harder. My first choice would be the Voyager Hypers in the 700x35 size.
If she is new to the commuting game, I strongly recommend fenders, even is she does not anticipate riding in the rain. There is always going to be the occasional puddle or damp surface that needs to be traversed, and fenders keep one from wearing it. Using fenders will impact maximum tire size.