No Allen wrench required. There is a latch in the lower rear of the backbox. Also two 3/8" bolts installed in the bottom of the backbox. Remove the backglass and take those 2 bolts out first. (9/16 wrench) At this point I like to securely shut the backbox and install the backglass. Make sure it is locked in place so the glass doesn't come out in transport. Then you can unsnap the latch in the back and the backbox is ready to lay down. Lay something like a towel, rug, or moving blanket on the cabinet before you lay the head down. As you are laying it forward, make sure no wires are tugging and binding.
Take your time and think it through. Would be great to bring a buddy with that has moved a pin before, especially for your first time. Could help a great deal. Good luck!

I cannot answer the question about the VW Atlas. If that buddy who helps you has a van or a pickup, that would be great.