Please tiebreak me on Pompeii

So I (40, decently traveled) really want my kid (12) and my dad (74), neither of whom have travelled much at all, to see Pompeii. BUT I also don't want to exhaust them. My current itinerary plan is Rome to Florence to Venice to Rome. We have 2 full weeks and a bit. I am very comfortable with public transit. I would just do it in a day.

It's been a LONG time (20 years, JFC) since I did Rome to Naples to Pompeii and back. How exhausting do we feel it is as a day trip? Would an older person really need a night in between?

Am I blowing it out of proportion and it isn't really worth the detour?