I have been trainin with women who is pear shaped. Her trouble area and most unconditioned part of her body is legs & thighs. Our workouts are focused on leg/butt. We do alot of cicuits w stregthening, cardio & now plymetrics for her lower body. I train her at her home 2x a week. She lost 5 lbs (goal is 10)and lots of inches everywhere except for thighs (only 1 inch). Its been 3 months.
The thyroid has an effect on metabolism. You mention she has been diagnosed with hypothyroidism. With her condition it will be much more challenging to lose weight.
The only thing I can suggest is resistance training for hypertrophy, however, that might pose a problem because she has RA.