Tweaking the start will be fairly easy.
The main issue is where the parcours for CP3 finishes. It might mean having to go via Switzerland rather than the Po valley.
Also, I expect there will be a finish parcours. Ideally they will take us into Brest by the old bridge as PBP did last time and then the harbour, like they did the time before, and stay down there as it is the only half-decent part of Brest. But the start of the parcours will influence what is the best route across France. So there are at least three stages not worth planning properly yet.
Tweaking the start will be fairly easy.
The main issue is where the parcours for CP3 finishes. It might mean having to go via Switzerland rather than the Po valley.
Also, I expect there will be a finish parcours. Ideally they will take us into Brest by the old bridge as PBP did last time and then the harbour, like they did the time before, and stay down there as it is the only half-decent part of Brest. But the start of the parcours will influence what is the best route across France. So there are at least three stages not worth planning properly yet.