What I've done so far with restaurants, because my family does enjoy at least 1 night out a week, is I try to search up [restaurant name] nutritional info on my phone while I'm waiting for my drink. If the restaurant has a website, they often have a pdf full of the meals they offer along with all the useful numbers.
I did eat at a smaller place and had to guess the carbs based on what I saw though, and because I haven't been diabetic for very long, it's not accurate.
Last night was tough. I went to a diner and their nutritional info said that if I wanted to eat an individual pizza, I'd need to take up to 50 units of insulin to cover the carbs in it - I am not usually taking more than 40U fast acting a day, so I skipped that option. I could have always ordered it and just had half, but still, more trouble than it's worth. I ended up having bacon/eggs/toast for far less hassle.