Hey I stayed at shojoshin-in at Koyasan and booked through Japaneseguesthouse. The temple was great, room beautiful with a garden view, and monks very friendly. Also very close to the cemetry which is great at dusk once the stone lanterns light up
Unfortunately I didn't stay in any other ryokans besides the temple lodging, it was all hotels centrally located for convenience. PM me if you'd like more info etc! Have a great time!