It's a gorgeous quilt, and the fact that she picked it out is even more meaningful. Bless you for making it for her. It will help in the tough times ahead.
Speaking as a Nurse Practitioner who is familiar with both chemotherapy and radiation, I can verify that the patients are often cold, and there are good reasons for that. The treatment suites are not designed for patient comfort, especially warmth. Bacteria breed in warm areas, so they're careful not to keep any area too warm. That cool-feeling circulating air is going through filters to screen out pathogens before it is returned to the suites, and it is constantly being recirculated. It must feel like a cold draft to someone in a hospital gown. Also, people often lose weight during this therapy, thus losing their natural layer of insulation. But there are several things you can do to combat that "cold all the time" feeling.
First of all, the quilt is a great idea. Just keep it simple and washable, and if anyone out there is going to make a quilt for someone undergoing cancer therapy, please, please, please ask them if they want any "ribbons" on their quilt. I can't tell you how many breast cancer patients (and others) who didn't want anything to do with Pink Ribbons until their ordeal was over, and when people brought them "Pink Ribbon motif" items, they went in the trash as soon as the people left. So be sensitive to that as well.
They may have to wear hospital gowns because of access to ports and lines and ECG leads and things like that. But generally, they can wear a pair of sweat pants without problems, and I highly recommend them. They are both warm and comfortable, and they will need to come from home. By the same token, a nice, thick pair of socks or some warm slippers, or both would be great. I know when my feet are cold, I'm cold. Just be sure to put those "grippers" on the bottoms of whatever she would be walking around in, either the socks or the slippers. It's a safety issue. If you don't put them on, the nurses will be forced to take them away from her, as much as they will hate doing it. So get those grippers on there! Also, the shoulders are often an area that lets in cold. They can't put their arms in sleeves. Someone is always coming along to take a blood pressure, or the line may be a long line in the arm, or lots of things. So a warm shawl that can just sit on their shoulders, and be pulled up around their necks, is often a welcome gift. Another thing that can warm people up is a simple hot water bottle. Just fill it with the hottest water you can get from the tap at the facility, wrap it in a towel, and place it at their "core", meaning their belly, or sometimes people like to hug them to the belly and lower chest. You won't be allowed an electric pad. As the patient becomes more fragile, they will burn more easily, so the hot water out of the tap is the best idea. It's usually not hot enough to burn, although of course you must test it. Every person I've given a hot water bottle to has thanked me profusely.
You have to remember, even the IV fluids they're giving are at least 25-30 degrees below body temperature. The IV fluids are at room temperature, so about 68 degrees. Humans are 98.6 degrees. That approximately 30 degrees is an important difference! Plus a lot of the chemo drugs have to be held in the refrigerator. They are taken out approximately two hours prior to the session, but they are no where near room temperature by the time the infusion begins. So they could easily be 30 to 50 degrees, or even more, below body temperature. This is a big reason why people feel so cold, all that cold fluid pouring into their veins. Yet you don't want the chemo to start to degrade before it's infused, so it really is a catch 22 on that one.
So bundle them up good, and give them something warm to sip on. Hot tea is good. Sometimes just holding a cup of hot tea and breathing in the warm vapors is enough. And that's OK. Whatever it takes.
Just a thought: When you've finished that quilt, you might think of doing a larger, heavier one to use on the couch at home, where they'll be a lot of the time. I've heard them tell me how lovely it is to have a larger quilt to look forward to cuddling under as soon as they get home.
That's all I can think of right now. Hope this helps!