I am a little uncomfortable with using cheats to force-kill the sometimes-pesky elders, even if it's the only way other than changing worlds.
On a somewhat unrelated note, for whenever a world move happens (either now or at the normal time), I'd recommend moving them the "old" way, i.e. saving the family to the library and putting them in a new file. Sounds like this save should be nuked.
So, returning to the main topic, how possible do
you think it is to have a normal-ish save using cheats to age the family up? I'd be a tiny bit more okay with that than an early world move, but sometimes it's just not worth it to stick around!