Jen,
Keep in mind that all the views stated are merely experiential opinions from people that have had a specific example applied to their lives. As far as me telling you one type of radiation is better than another, I do not believe even the highly qualified medical folks can give you a 100% answer. If you are not sure of what the radiation oncologist is telling you in terms of what are the options available, what are the pros/cons with each, what is the specific recommendation and why, you did not ask enough questions. Places such as M D Anderson in Houston which is one of the best HNC centers in the US, would gladly conduct a telephone consult with your radiation oncologist and tell you they agree or disagree and why. This process typically takes 3-5 days and usually your treating physician would welcome another set of qualified eyes reviewing things before you start.
Along the same lines, many doctors in this area place a port-a-cath or medport in your upper chest when they plae the PEG tube. This allows a direct connection to a main artery and avoids issues with chemo, fluids, blood draws, etc. It was invaluable in my case when I had to resort to IV feedings for several weeks plus I used it for IV fluids for several months. My wife was trained to replace the access needle every 3 days and we did all of the feedings and fluids in the comfort of our home (or my discomfort as it turned out

).
Keep asking the questions now before you begin. Once you start, you will most likely not be able to change the course. Use the face time with your treatment team to COMPLETELY satisfy your questions and concerns.
Even though the PET/Ct takes a while, it is probably one of the most effective diagnostic tools available. There is a great study published in the Annals of Otolaryngology last month that shows some great data on the PET/Ct which I am assuming you are going to get. They also will require you to take some type of tranquilizers so even your swallowing muscles are settled before the tests begin. It will be easier than post radiation when you get to repeat it but you will already be a seasoned "pro" by then!
Eat a lot now, rest as much as possible, even if you have to take meds to do so. A rested mind will approach this journey much better than a fatigued one.
Take care,
Ed