As per Rick Steves recommendation I have gone online to www.museicivicivenziani.it to try and purchase tickets. I am unable to get past the request for the codice fiscale (ID document). It will take all my information, but won't let me continue to purchase. Another site Vivaticket will allow me to buy. It's 6 euros more. After all of this my question is can someone help me navigate the original site. Or are there any problems with purchasing from the Vivaticket site? Thanks.
You can create one here: http://www.comuni.it/servizi/codfisc/
It wants your passport # in lieu of a tax ID