hi, my son is coeliac and when we visited italy last year we took quite a lot of his stuff with us. GF pasta and biscuits are quite easy to find in
supermarkets, the PAM chain are particularly good. If you go here
http://www.celiachia.it/
you can get good info about the region you are visiting. There are now a number of restaurants which have GF menus, they are given certificates by the GF food companies, and have to know all about cross-contamination, etc. Check local listings magazines too, these restaurants are beginning to advertise the fact that they have menus 'senza glutine'. The celiachia site should also be able to give you a list. We went to a restaurant where my son had a fantastic GF pizza! The manager came and chatted to us and said it's slowly but surely picking up in Italy, so I hope you can find somewhere.
The thing we found hardest to buy was GF bread, luckily we took some of our own. I've also heard rumours about GF bakeries!
One last thing, when we posted to the celiachia site, we asked if they could put us in touch with someone locally for advice, and a local girl did contact us, and came to meet us with loads of GF treats for our son!
Hope this helps, have a fab holiday! Jane x