Khao San Road’s reputation – as a place of hedonism where countless backpackers’ drunken dreams have quickly become SangSom-fuelled hangovers of nightmare proportions – was immortalised in Alex Garland’s cult 1996 novel, The Beach, and later in the critically panned film of the same name, starring Leonardo DiCaprio.Once thronged by budget travellers in search of budget thrills, for whom the all-night party started in the 1980s and only got more debauched as the decades passed, the 410-metre…