I have made this exactly, and also with some modifications. Both turned out great! I did used 2 cups of honey roasted peanuts, because pecans are ridiculously expensive and I prefer peanuts. I added the pretzels in with the nuts and graham cereal, before pouring the syrup mixture over. I found 1 1/2 the normal amount of syrup was too much. So I used 1/2 cup of butter plus 2 tablespoons, 1 1/4 cup of brown sugar and slightly more than 1/3 cup corn syrup. Came out perfectly!
My family loves this. I made a few modifications, I rated 4 stars because I felt the modifications were needed. I subbed 2 cups of honey roasted peanuts for the 1 cup of peanuts/1 cup of pecans because the honey roasted peanuts come in 2cup jars. I added more pretzels and broke them up a bit. I multiplied the caramel mixture by 1 1/2 and added the pretzels to the cereal and nuts when baking. We used pretzel M&M's. Simply outstanding. Second batch in a week.