An absolute must do !!
This place is incredible.
I would recommend starting the day with a guided tour so get in lots of facts and information about Pompeii. It’s impossible to do everywhere in one day so it’s useful to start off with highlights and recommendations on where to go. We went with Askos tours and loved them.
We spent 2 hours with the tour and then wondered for 3 hours by ourselves afterwards. Would not want to rush to do Mount Vesuvius or Herculaneum before / afterwards.
I would recommend visiting a viewpoint, a grand Roman home (e.g. House of Loreius Tiburtinus), and the amphitheatre. Overall just wonder around and you will stumble upon amazing sights.
As we went in January, it was fairly quiet and we were told it gets up to 10,000 people in the summer months which does seem hellish. Would definitely recommend going in the off season.
There were paths marked out that were accessible to wheelchair users, but this was less than half of the area.