It does suck having all these special foods for the LO's. You will get be really organised with it. One step at a time, luckily it all starts out slowly, you'll have plent yof time to come up with recipes and tweak things.
For holidays, we went when K was 8 months. I took a huge esky of prepared food frozen from my freezer - GF breads, all his allowed veges finely chopped raw ready for cooking, pre made meat and lentil patties, a stock of his fruits, all his dry foods. Then on holidays I didn't have to worry about buying much for him and I could thaw and cook each day or thaw and reheat everything he needed. It worked out really well actually.
Now we are thinking of going overseas when he is 15 months, but we have decided to stay somewhere that has a kitchen, and I will take as many dry goods as I can in my luggage to save hassle. It will be only for two weeks, surely we can get by.