Well, this actually doesn't work. If you need to drop an item far from the start that's not an option. As soon as you open the drop menu then you get off your board. Then you have like 1 second before the game automatically sets you back to the session marker. So, I guess if you're fast enough with the controls maybe you could do this, but not really an option. I also tried placing items outside of the challenge then entering the challenge, but that doesn't work either. The placed items don't persist into the challenge.