Aw Beth,
I'm sorry to hear about your dining experience. Sometimes I deal with sensory overload issues myself and I understand exactly what you're saying. It gets so bad for me that I have trouble swallowing on top of it all.
Don't give up, you've gotten some great suggestions. What DH and I do on the rare occasion we go to a sit-down restaurant is hit in between the high traffic times. He can't stand the crowds which is great for me.

We try to go somewhere between the lunch and dinner crowds and it's not uncommon for us to be the only ones there! It really is nice to have the whole restaurant to yourself.