I was diagnosed with liver disease 2 years ago (non alcoholic steatohepatitis) and have been on an extremely restricted diet ever since. Now with that said, it is exactly the opposite of what your wife is doing. I am on a high fat Carnivore diet. But, I can speak to dealing with the restrictions while traveling.
First, having an RV makes this much easier. We do the vast majority of our cooking at the RV and either bring most of our supplies with us and make needed trips to grocery stores while we are on the road.
When eating out, I am upfront with the wait staff before we order. I just tell them that due to my health issues, this is what I am ordering....meat only, no veggies or carbs of any kind on my plate, etc. 99% of the time they are more than happy to accommodate. I have also found that privately owned restaurants are generally much easier to navigate than the chain places. But I have been able to work it out almost anywhere.
Tell your wife that it will take time to find out what works for her. But don't be afraid to ask. I can't tell you how many times I've had steak and eggs at places that don't even have it listed on the menu, just by asking.
2017 Jay Feather 7 22BHM Baja/Andersen WD
2018 F150 4x4 3.5L Ecoboost Max Tow
2015 MB Sprinter 2500 Passenger 2.1L Diesel
2007 Ram 2500 4x4 Cummins 5.9L G56