You sure can bring food back very easily to your B and B in Italy. I have been in Italy sola for 3 months now and I have brought food back to my B and B every night. In Italy "carry out" is called "take away" or "Porta Via." Many bars, delis, panino shops, pizza places, and ristorante know what "take away" or "Porta Via" means. In fact, in Firenze it was very common for shops to ask me first if I wanted "take away." Then they would tell me to ask for "Porta Via." But that was Firenze, possibly the most "HIP" città in Italy.
However, there are places in Italy that may not know "Porta Via" because "take away" is not a common social/cultural practice over many parts of Italy. So before you order, say this to the person helping you: "Io vorrei portare via il cibo alla mia camera," or "Io voglio portare via il cibo alla mia camera." Find someone at your B and B to help with pronunciation. I have never had a place decline my preference for "take away" or "Porta Via." But if you have to shop around, you will find places who will love you and "Porta Via" you.
I don"t recommend saying "Porta Via" nor even "Porto Via," the first person grammar. I said "Porto Via" to a cameriere in Amaseno and the person was clueless, picked up my leftovers, carried them to the kitchen, and threw all the delicious food in the trash. I should have said "io voglio portare via gli avanzi alla mia camera." And pointing to myself would have helped too. When the kitchen realized what I wanted, the Chefs made a whole new plate for me and wrapped it up for me to carry out.
So let Italians love you Kristen, they know it is Not easy to travel alone, let them help you, Italians love knowing they can help you. Hey keep in touch and let me know how things are going,
Love,
San