JPT68,
I'm sorry to hear you're having extensive surgery, and understand your concerns. I'm glad the doctors feel they can get this cancer, otherwise they wouldn't be doing it, so that's a positive sign, plus being at the top cancer center in the country.
I had intraoperative radiation, IORT, twice to the same left neck, once in 2012 was with a pec flap to protect the carotid artery after the neck muscle was removed in 2011, and in order to have more radiation, which IORT was followed by IMRT, and Proton Therapy in 2013. The surgeries were about the same duration, required the ENT and Radition Oncologist, support staff in the OR, shielded room, but the boost dose radiation wasn't for another month I guess due to healing from prior radiation to the same area.
Good luck with everything.