Hi @mariondot40, I totally empathize with you as I am in much the same situation! We started caravanning 18 months ago, and will be doing more in future. And whenever I am away from home, controlling what I eat seems to be much more difficult and I invariably put in weight. In my early days of 5:2, I used to lose it easily with 2-3 fasts in quick succession, but nowadays I find that much harder.
If I am active when away, the damage is certainly less, and generally we are active when on holiday (eg the 5 hour strenuous bush walk and climb we did yesterday!). So do lots of walking, swimming, cycling, canoeing, whatever you can while on holiday.
With regard to fasting, I have managed the odd fast day on previous trips, but have decided that if I don't feel like it, I am not going to - as per @lovemyparrot's advice to me!! If we are doing a lot of driving in the morning, I do try not to eat then (as once I start eating, I need to keep eating or else I get nauseous) so can do a partial fast.
Food-wise, at home I do have breakfast most days now, although for a long while I had given up breakfast as per so many here. (I reintroduced it on advice from carorees when I was battling constant hunger, and it helped with that tremendously.) Now I really try to use how hungry I am as the decider as to whether to have breakfast. And I seem to manage that okay. At home, I have scrambled eggs and porridge, but while away, cereal is easier and I so enjoy that!
If I have gone without breakfast, I do try to have as long a fasting period as I can. Very occasionally I might go without lunch, but generally just have lunch as late as possible. But I don't restrict my calories to fast day amounts!!
For lunch, if we are going to be out and about I prepare a ham and cheese sandwich with lettuce leaves instead of bread - thanks to forum members for that suggestion

- and lots of salad veggies that are easy as finger food. If at the camp, I make up a huge mixed salad with tinned tuna or salmon. Dinner is usually a stir fry, curry, a multi-veg meal of some description. And berries/orange for dessert.
But I do also have carbs - this trip we have been having a hot cross bun with butter for afternoon tea. And some creamed rice as well for dessert. And a chocolate biscuit or 2. And cakes if we visit a bakery. I still love all these foods. And if I have been very active, I find the carbs much more satisfying and enjoyable than protein and fats (though I do have nuts and cheese as snacks).
However, we don't visit bakeries and cafes and tea shops (etc) very often - or I would be having a lot more carbs. So perhaps you can limit the eating out to only a couple of times a week...???
Daytime is not too bad for managing my food intake as we are generally busy. Evenings are the problem, just like when I am at home... too much chocolate... Having a very satisfying dinner and dessert helps. And not having that first piece of chocolate...
I am trying to use hunger and what I really fancy as my guide as to what to eat. I do try to select the healthier alternatives first (might not sound like it!!) but if I want that buttered bun, I will have it, and enjoy it.
As others have said, having a good time is the most important thing, and I am sure that is what you are doing.

You know what strategies work for you in managing your eating, so try to employ as many of those as you can.
Good luck and best wishes

and happy camping!