The road curves north and heads into Frailey Township, becoming North Tremont Road and running through forests. PA 125 heads into the residential community of Donaldson and becomes South Maple Street, turning west onto East Center Street. The road continues through more of the community and becomes West Center Street before leaving Donaldson and heading into more forests, running a short distance to the north of the Reading Blue Mountain and Northern Railroad line. The route passes under I-81 prior to heading into Porter Township and becoming East Center Street. PA 125 reaches the community of Good Spring, where it turns north onto Main Street, heading into Hegins Township and becoming South Good Spring Road. The road curves northeast to ascend Broad Mountain before a turn to the northwest to descend the mountain. The route runs north through the wooded residential community of Lamberson and continues into agricultural areas with a few homes. PA 125 enters the residential community of Hegins, where it crosses PA 25 and becomes North Good Spring Road. The road heads through more farmland with some woods and homes before heading into forested areas and turning northwest to ascend Mahantango Mountain. The route enters Eldred Township and becomes Vista Road, descending the mountain. PA 125 turns to the north to head into an agricultural valley with some woods and residences, curving northwest before heading more to the north. The route continues farther north before turning west onto Main Road.