If I were designing something like a box in fusion 360 meant to eventually be machined out of a single piece of material, is there an efficient way to move between the assembled mock-up and an exploded, cut list style layout where all the bodies/components are on the same plane and positioned for toolpathing?
Not yet, that is something that they have been talking about as a future feature.
What I do is to make copies of all of the components in Fusion360 and lay them out manually on a sheet using joints. You can carry on tweaking the design and the components that are laid out on the sheet will auto update as long as you did a paste and not “paste new”. By using joints on the layout, they will automatically shuffle themselves around so they don’t overlap.
Bit of a pain to setup, but once you have done it, as long as you don’t make major changes, should be fine.
Why don’t you put post an idea to them explaining how you would like it to work better?