I grew up not a million miles from there. It’s oft touted as a druggie town but I don’t think it’s that much worse than other places tbh. Certain areas to avoid, but that’s not unlike city life, and depending on where you come from it won’t be an issue. You might not even register it. Party drugs are rife in the area in general, though it took me coming home from university to spot that.
West Cornwall, and Cornwall in general, is quite deprived. I would recommend watching Simon Reeve’s documentary on BBC iPlayer; he’s spot on when he says ‘there are jobs but no careers’ so many ‘Cornish Maids’ like me left at 18 for university and never looked back. The same might be true of your kids.
We holidayed in Treen this year which is about 15 minutes west of Penzance, and spent a fair bit of time on PZ Promenade which was actually very pleasant and much less busy than St Ives (where we didn’t stop).
Schooling in Cornwall is different to here - people tend to have the choice of just one school. There are two in PZ, Humphry Davy and Mounts Bay (in Heamoor). There was always the impression that MB was the ‘better school’ and some PZ town kids went out to MB, but I have friends who went to both (20 years ago mind) and all did well for themselves in their own way (I met them at A level, so would have been the more academic kids from both schools). I have no idea about autism provision in either school, but you don’t specify if you’re looking for mainstream or not.
What will you be doing for employment? Will you be working in PZ or commuting?
I guess we don’t really have enough info about where you are now to pass judgement on whether PZ is better or worse. I live in leafy city suburbs in the SE and I would consider PZ as acceptable in parts, but I would also consider living more rurally.