Mise en place (always!).
Combine peanut butter and chocolate chips in a small microwave-safe bowl. Microwave for 30 seconds at 50% power. Stir, even if nothing looks melted. Cook another 30 seconds at 50% power. Stir again. Microwave at additional 15 second intervals (50% power) as needed. Be very careful not to overheat chocolate.
Stir 3/4 cup of marshmallows into melted chocolate and peanut butter until melted. Microwave for 15 seconds at 50% power if needed to melt marshmallows.
Pour Golden Grahams in a large bowl. Pour chocolate/peanut butter/marshmallow mixture over. Stir until all the Golden Grahams are well-coated.
Pour 1/2 of powdered sugar into a large Ziploc bag. Add 1/2 of Golden Graham mixture. Toss until everything is well-coated and any chunks are mostly broken up.
Spread out on making sheet to dry. Repeat with remaining powdered sugar and Golden Grahams.
Toss dried puppy chow with remaining 3/4 C. of mini-marshmallows and broken up Hershey's bars.
If it's not all eaten immediately, store in an airtight container. Hiding this dessert might be advisable.