hello again,
I have had a chance to look for trains.
I do agree that the TrenItalia website is not very helpful!
This one at least shows you approx 4 trains around the time you enter.
The journey time Milan to Verona is about one and a half hours.
The only problem I can forsee is that the performance may end AFTER the last Verona~Milan train has left,but it will need thorough searching of this website to confirm or otherwise.
http://plannerint.b-r...query.exe/en?L=profi&
If the last train to Milan is before the performance ends,I can only suggest staying in a cheap pensione;but id you do decide this do it soon as these places DO get booked up early.