Try downloading at different times.
By the way, Axe, it occurred to me that the ability to pass through by shifting from the center of the map doesn't speed up the process much, maybe a day at most. After all, you could have leveled up a Pyromancer with Armageddon (considering the amount of exp gained in battles) and wiped everyone out.

Well yeah, probably. There are definitely several options for a power Walkthrough as well. It's just that in those, effectively only ONE first day is allocated to leveling up fighters. On the second day, for example, two heroes (a scout and a powerhouse) need to head toward the black dragons from the nearest Fortress. They should carry 2 graves with them. In battles, use freeze potions utilizing the terrain of the combat area and magic. The difficulty is breaking through the Black Dragons, on whom magic doesn't work. But you could probably have managed to hire minotaurs for this task. A witcher can't scare Black Dragons :) And you can probably try to fit it into three days as well.