Thanks for the ideas bxcc.  For 2.1s those WTBs are light and very reasonably priced.  Yes, I really want to stick to 1.5 or at most 1.75.  She will ride mostly rail to trails and mostly light gravel and crushed limestone paths with some asphalt.  At 100 lbs. I am looking to set up a light bike for her.  Since posting I have spent a lot of time looking and perhaps the Panaracer Pasela 1.5 or 1.75 tires will be a good match.  Those carbon wheels of yours would be sweet but I have a pair of Mavics that will have to do at about 1800.  I also have a budget.    It will be fun putting this together and I'll post some progress pics.  This website is a great resource.