A few random thoughts.
A. It will be hard to come up with a self-propelled trip that is genuinely original.
B. Such a trip could be logistically expensive.
C. If you announce your idea somebody could beat you to it.
D. How much time would you have to complete such an adventure?
E. Would this be a hiking trip? Or multi-modal? Like Hike-Bike-Raft?
F. Eric Ryback, PCT Hiker #1, used a 375 mile resupply plan. So, that's been done. Try 400+ miles?
G. Original, self-directed research and planning. Asking the internet community to do your research for you is poor form.
Extremely random thought:
CDT. October 1 start. An insane idea. A person could get kilt, or even worse.
Something a bit more manageable:
Piece together the longest hike without a road crossing in the Lower 48 states. That could be fun. Tipi Walter might approve.
Cheers!
Wayne