Shooting buildings at least in an urban environment typically means a wideangle lens. Interiors, definitely wideangle. While there's no lens that goes from a true wide for architecture (I'd say at least 21mm equivalent or wider, or 14mm in a DX lens) to mid-tele (75-85 mm equivalent) needed for a wide range of landscape shots, the 16-85 for approximately 24mm equivalent at the wide end comes closest in Nikon lenses. The extra 2mm gives more than 25% more area in the image, which can be important in tight urban spaces or interiors to get what you want in the image.
A two-lens kit emphasizing architecture and landscapes would be the 12-24 or 10-24, or perhaps a third-party wide for less, plus a mid-range zoom. The very moderately priced and capable 18-55 VR would be fine with the wide to give a full range of approaches to her subjects. Unless of course she likes shooting portraits, in which case the 50mm f/1.8 might be the economy-class portrait lens to combine with a wide lens.