I know how you feel at a loss. Maybe ask your current doctors of any other treatments, where offered, suggestions. Sometimes they don't say directly to go here or there, elsewhere without asking. Some may say it won't work, as was my case with brachytherapy or refusal to do more radiation due to dose limit toxicities.
I also looked at all the top hospitals via the internet, see what they specialized in for head and neck cancer, who the doctors were, their background, mostly in my area, but other hospitals may give an idea of the latest treatments. U,S. News Reports Best Hospitals was helpful, had many links.
You don't have to be restricted to one area. You can stay at Hope Lodge, other housing, and go anyplace if insurance allows. Sometimes a visit to one city can enable a number of consultations.
I basically googled everything, went to various sites for trials, pubmed abstracts, etc.
Then I called the hospitals I wanted to consult with.
You can see in everyone's signature what treatments they had. Unfortunately, I didn't join here until 2012, and usually don't ask for advise on other sites.
I made sure or was in the process to have a copy of every scan, CD disk too, pathology, surgical reports, radiation plan, and in some cases copies of the pathology reports. I also made a time-line of my case being it was complicated.
The more information I had the better. It's a lot of work, but it helped me in a number of ways, and felt more in control, that I didn't have to accept what was offered, although that was an option still on the table, but could go elsewhere.
Sometimes time changes treatment options too. For a year I could not do further treatment, but physical,medical condition improved, I was able to do more, and doctors do take that, amongst others, into consideration.
I hope this helps