Few will deny that U of Washington is number one for primary care. It has exceptional opportunities for training at rural sites. The unfortunate thing is that it accepts few students from other than Washington, Wyoming, Alaska, Montana, and Idaho.
U of Washington in Seattle. They are the only med school in the Northwest and serve most of those states. They have been ranked #1 in primary care. They have tons of programs for med students and pre-meds alike to encourage practice in primary care.