This is my well-trodden patch and plenty to chose from. Close to Capel Garmon are the remains of Maen Pebyll and the views are stunning from Maen Y Bardd above the village of Rowan across the Conway Valley. I have often used a great little book "Walks in Ancient Wales" by Robert Harris (ISBN: 978-1-85058-797-2) alongside the OS map to get around. So close to the gem that is Anglesey too. Happy days!