You will most likely be pleased with your choice of proton beam therapy as your treatment. I did a lot of investigation into that procedure before I made a final decision and I concluded that it was an excellent option for my case and, looking at your early stage disease, it will probably be great for you.
However, I hope you have not totally bought into the buzz about "no side effects". While it is certainly non-invasive as compared to surgery, you are likely to experience some side effects...perhaps frequency and urgency of urination and ED is also a possibility. I had extensive conversations with the docs at the University of Florida Proton Center in Jacksonville and they were forthright in telling me that this, while a great treatment, it is not without possible SE's. I am truly not trying to rain on your parade because I do believe this is an excellent treatment choice, but I hope you will recognize that it's still not a miracle cure...
Shown below, for your info and persepective is a quote from last April's issue of US News wherein there was a nice story on this treatment.
"...But certain doctors—not to mention the occasional patient who has experienced side effects from proton therapy—wonder whether the high-tech allure of protons hasn't outpaced the science. "Because of Internet buzz, the morbidity associated with proton beam therapy is underappreciated," says Anthony Zietman, a radiation oncologist at Mass General who specializes in prostate cancer. Many of his patients, he says, are surprised to learn that proton beam therapy exposes the bladder and rectum to high doses of radiation and does, in fact, carry a significant risk of causing impotence. Although preliminary research has suggested protons may be superior to conventional radiation for prostate cancer, there's a lack of randomized studies (the type doctors consider most rigorous) comparing the two—and standard radiation techniques are improving all the time..."