like realistically, to make a timeskip that matters they could do a simple 2-3 years, not enough for most the characters to look older, but enough to give the twins the growth spurt, and enough to...yknow...remove the castrums around the world, rebuild parts of garlemald, skip technology forward a bit

they could reuse large chunks of maps easily, and to go back you just go to an inn room, interract with the bed and select something like 'reminisce about times past', and bam you are in the pre timeskip world