Ruggedly beautiful, and only a couple of hours from several major cities, it's no wonder that Snowdonia draws the crowds. During this year's visitor boom it's likely to be busier than ever, says Dan Aspel. But away from the over-trodden hills in the north of the park, there's plenty of peace to be found. To help spread the load in our National Parks, and enjoy a more relaxed visit, in this series we suggest quieter alternatives to the bustling hotspots.