Hi Doug and welcome!
Phyllis here in Boston and know of what you speak. Please give my best wishes to your daughter and tell her (and your family) that we are here for you!
Proton is done here in Boston at MGH... I think there is one out at Loma Linda in CA as well. Not sure about a 3rd facility but I think one does exist.
I just had Cyberknife done at Beth Israel here in town. I think there is a gentlemen here that just completed his Proton treatments at Loma Linda and if you look through this "Radiiation/Radiosurgery" forum, you should see his posts. My short term memory is in place so I'm sorry I cannot remember if it's Gary or Paul.
As your daughter is young and the residual is small, radiation is a terrific choice of treatment. There are many safe options available (via Gamma Knife, Cyberknife, Proton and FSR). Reading some of the threads here about all of these forms of radiosurgery would be a good start as to advantages/disadvantages of one over another. I truly believe it's a personal choice as to which one is choosen. For me, I based my decision on accuracy of the treatment (heck, if they are going to beam me, they better hit the thing!), the comfort level of the procedure, as well as the opportunity to have the healthy tissue recupe from the treatments. All are very viable options in radio-surgery.
Any of us are here for you to help answer any questions... we truly do understand!
Happy holiday weekend to you and your family. My best wishes to your daughter. Please tell her to hang tough and we're here for you all!
Phyllis