You could also take a look at the North Wales Rover Ticket from Arriva
It's zone based for bus and train across north Wales on a daily basis. Also, it can be used on some other local operator routes and can give discounts on some attractions.
You would need to start within a zone, perhaps from Chester or Wrexham, but that needn't be too expensive.
There are other explorers for longer periods and different parts of Wales, e.g., the Explore Wales Pass.