As a general comment, this is a difficult issue all round, and it's not just travelling outside your own country, but also in unfamiliar places within your country. The further away you are from major conurbations or places familiar with mass tourism, the less likely you are to easily find places where there are significant eating options.

I find the London suburbs, and the East Bay outside San Francisco to be very difficult (I'm gluten intolerant rather than coeliac, so it's not life threatening but still a significant issue). Regularly I get looks of complete incomprehension from waitstaff, who appear never to have heard of the GF issue. And work lunches become very tricky.

I've found the best plan is to travel with some ZipLoc bags and, as soon as possible after arrival, go to the local supermarket and buy a supply of emergency snacks, to bring out and eat at restaurants which don't provide suitable food, and at work lunches where all that is available is sandwiches.