I have smoked chicken thighs a few times now and have run into the same problem. Mainly, the skin is rubbery. The meat itself is really good, but I can't even eat the skin. I marinated 12 chicken thighs in a bottle of italian dressing for ~15 hrs, took them out and put a rub on, smoked for ~1.75 hrs, wrapped in aluminum foil for 30 minutes, then threw the thighs on a medium temp grill and basted them with a bbq glaze for roughly 10 minutes, partly indirectly. Am I doing something wrong? How do you get the skin crispy? Thanks for the feedback!