Congrats on finishing treatment Darrell. From approx. the 4th week of radiation on I only drank water. I had a tube and made good use of it. I didn't even attempt to eat anything, just drank non-stop water and used the tube. I finished last July 10th and kept and used the tube until December. It was at least two months after treatment that I was eating anything substantial, I kept drinking water so my swallowing function was good, and I did milk shakes, etc. What I also did was stretch my jaw constantly to avoid trismus. I have full range as far as opening my mouth.
Patience Darrell, in my experience the weeks after end of treatment were my personal worst. I expected to eat AND to feel better immediately and that didn't happen.
Good luck to you!

SCC Left Mandible. Jaw replaced with bone from leg. Neck disection, 37 radiation treatments. Recurrence 8-28-07, stage 2, tongue. One third of tongue removed 10-4-07. 5-23-08 chemo started for tumor behind swallowing passage, Our good friend and much loved OCF member Minnie has been lost to the disease (RIP 10-29-08). We will all miss her greatly.