JT2,
You didn't say whether your rad treatment was IMRT or XRT. The likelyhood of your saliva returning, at least some, is much better with IMRT.
I pretty much lost all of my saliva initially, but it has slowly returned over 3 years. It started coming back at around the one year point, and continues to improve. I still need liquids to eat, but the water bottle is not required ALL of the time like it was. I'm able to go for a 3 to 5 mile run without it. Just a piece of the dry-mouth gum.
My sense of taste gradually returned to near normal after 12 to 18 months. There are some things that still don't taste right, and I still can't tolerate spicey foods, but improvements continue.

As far as the range of motion (trismus) issues and swallowing, does your health service have a speech and swallowing therapist available?
Mine did, and her assistance was invaluable in returning to near normal. She prescribed a device called the Therabite which helped me to stretch my mouth open slowly over several months, and she also performed a swallowing study which identified where my problems were, and allowed her to prescribe a series of swallowing exercises to improve the swallowing function.

I hope this info is helpful.

Hang in there, the improvements are frustratingly slow sometimes, but things continue to get better.

Good Health,

Chuck