Congratulations on your new rig! When we moved from our 2010 to our 2017 we had the same issue, but once we got it all set there were actually better places in the new rig for our stuff but we just had to give it some thought and work with it a while. We also have a 3720 and the little outside extra storage is great for all the hookup parts once we got the right containers from Walmart to keep them all away from each other.
Dick, Joyce, Diego, Picatso and Gustav
2017 3720 RL, and 2013 HC 343RL
2017 3500 Dodge Maxi DRW 4X4, Pullrite Hitch, IS, Disk Brakes, 3rd AC, Winegard Traveler, Bathroom door mod, Dometic 320, couch for desk swap, etc.