Tx,
Welcome to HW. As much as we'd like to not have any new company, we're here, and the door is open.
You are goingt to get a lot of questions on choices of treatment, so I'll not go there. I expect that you have talked with multiple surgeons and Rad. Therapists in the process of a decision.
I did adjuvant IGRT (after surgery), but the basic side effects are pretty much the same. At my clinic, I met a number of men who were doing RT as primary treatment. All of us are "Calypso" guys - a marker that they plant into the prostate much like the gold markers. In my case they were planted into the scar tissue.
I will say that the guys who were "primary" treatment got along a lot better than I did (seriously - we had quite the discussions). Most did not have any real urinary issues. Mine were from the surgery, worsened a bit by the RT. We all had fatigue, some less than others. Only a few had real bowel issues (again, if you had surgery or past colo-rectal issues - I had both, they may be problematic).
My day-by-day report is in the thread linked from my signature (below).
Welcome again, and let us know as you have questions, or just need to vent.