Welcome to OCF, Tim! You're in the right place to get info and support. We will help as much as we can, just remember we arent doctors, we're patients/survivors and caregivers.
The best places to get treated for oral cancer (OC) would be at a comprehensive cancer center (CCC). Off the top of my head the best are MD Anderson, Sloan Kettering, Johns Hopkins. Ive included the links to the list below. For a complex case, your wife should if possible get at least one more opinion. She is facing a long difficult road but it is doable, especially when you have people who have been down that path before helping you. OCF has members all over the world. Im sure the best treatment center would greatly differ depending on who you spoke to. There are websites that rate doctors/hospitals (not sure what their criteria is), Ive given you the best places to go The National Cancer Institute and US News Best Hospitals to find the countries top facilities.
For right now, your wife should do her best to eat all her favorite foods, desserts too. Her ability to eat is going to be temporarily compromised with going thru a major surgery and afterwards her doctors may suggest radiation treatments to ensure all the cancer is gone. She does not want to be in the middle of treatments or recovery and suddenly get cravings for something she isnt able to eat. When a patient has cancer or is in the recovery phase they burn up calories at an incredible rate. Maintaining a persons weight is a crucial part of treatment and recovery, the less weight loss the better the patient is doing.
If you end up traveling for treatment, there are free or very inexpensive ($10/night) places to stay near most of the CCCs. Hope lodge is one of the most common ones. There are even airlines that provide free seats for cancer patients who are traveling for their treatments. I dont know about availability but Id suspect these things would be in great demand. The link is below for that as well.
List of Cancer CentersUS News Best Hospitals ListMain OCF Website... Financial Assistance including Air travel/Lodging