When I look at their designs Terry bicycles seem more suited to fast rides or at the best light touring. For instance, even on their most "touring worthy" models, clearance seems tight for wide tires (say 28 to 32 mm wide) and fenders. Their smaller frames also use a 700c rear wheel and a 24" front wheel. As someone who currently tours with a child on a trailercycle, I find the dual-sizing rather inconvenient when touring: 2 tube sizes to carry, 2 tires on longer trips, etc.
Basically, any decent bike with 26" tires could be designed adequately for her. For day rides and light touring, some "junior racing" frames might work if they have adequate clearances, eyelets for racks, etc. If her mixte fits her well, is good looking and if it is a good quality frame (a few were, most weren't top notch), another solution might be to upgrade the drivetrain. Not the cheapest solution, but it may be a decent one.