What exactly were Zoraal Ja's logistical war plans?

[Cleretic]

Or has he just never bothered to inquire as to the experiences of a single returned Silverscale regarding just how long and complex the journey across the salt actually is?

That, basically.

Zoraal Ja has a demonstrably hugely inflated image of his own combat prowess, and that's an image that probably extends to his view of the people he commands. But you watch him during the rite of succession, and even afterwards in the first attack on Tuliyollal, and you see that his ego is his only plan. He's a Soulsborne player who thinks the only way to play the game is 'solo dex build', his plan is just to personally walk in there and brute force the solution. His war plan against the Three Great Continents was absolutely to just sail east and take his twinfangs to the first world leader he sets his eyes on.

And weirdly, that might actually get him somewhere? I don't know if he'd beeline for Garlemald or just start an eastward push with the first place he sets land on, but both of those are pretty good starts; if he goes for Garlemald he's basically just aiming at a bunch of spineless bureaucrats that are the only guys left in charge, he can easily handle that. If he just starts where he finds himself there's even chance he either starts in Limsa or Sharlayan; Limsa's not looking great for him but he might get the first strike, and he can absolutely overpower Old Sharlayan. His step two is a failure in every single scenario, but the step one might actually work.