Line the base and sides of an 8 x 8 or 9 x 9 baking pan with wax paper and set aside.
Roughly chop macadamias, marshmallows and candy and place in a glass or stainless steel bowl. Add the pistachios and cranberries and mix gently. Reserve a bit of the mixture for the top if desired.
Break the chocolate into small pieces (unless using chips) and place in a microwave safe bowl. Microwave for approximately 45 – 50 seconds, then stir. Microwave for another 30 seconds then stir again. Repeat the process if necessary, until all the white chocolate is evenly melted and has reached a relatively thin consistency. Be careful not to burn the chocolate - a few unmelted lumps are better than burned candy.
Pour the melted chocolate over the fruit, nut and candy mixture and mix well to ensure all pieces are thoroughly covered in chocolate. Pour into the prepared pan and then level with a spatula. If you saved some of the mixture to sprinkle over the top, do so now. Cover loosely and refrigerate for at least two hours or until set, then remove from the fridge, place on a cutting board (the paper will be very easy to peel off) and cut into your desired shapes and sizes.
This will keep very well for at least a week in a sealed container at room temperature, though it may soften slightly at warmer "room temperatures" - and it probably won't last a week without being eaten!
*If you require a longer shelf life for your White Chocolate Rocky Road or want to make this nut free, replace the nuts with different types of dried fruit or candy.