Melt the butter and pour in a 9 x 13 pan, spreading it out as much as possible.  Crush the graham crackers (I put them in a plastic bag and use a rolling pin to crush them) and sprinkle them on the butter.  Sprinkle on the chocolate chips, the butterscotch chips, and the coconut.  Drizzle on the condensed milk with a spoon (don't worry about trying to cover every spot), and lastly sprinkle on the crushed walnuts.  Bake at 350^o for approximately 10 - 15 minutes, until the edges are golden brown.  While still warm, run a knife along the edges to keep the bars from sticking to the pan.  Cut into bars when cool, then store in the refrigerator--or garage, in my case.  Too far away for me to grab one easily!