@Mura_Megami The trophy only says that you must play the same family for 10/26 generations. So long as you don't change families and stay with your original family that you started day one, you can move wherever you like.
I started my 26 gen family in Oasis Springs and stayed there unil I finished the "challenge" I was playing (10 Generations), but then after that my sim legacy family lived in San Myshuno, Windenburg, Sulani, and Glimmerbrook.
So don't be afraid to move them to another world, you just have to stay with the same family.
