I deal with this sort of situation all the time. I’ve never eaten every few hours because I felt it was “good for muscle growth”, it’s always been more about NEEDING to in order to keep my energy levels up and my hunger at bay. I’m Italian, we are hungry every 45 minutes
So here’s my advice. Obviously, the best scenario is to have food available, whether it be a protein bar or even something like an apple and/or almonds. But, sometimes that is not possible and we are stuck in situations where we can’t. So then you’re stuck with what’s there. For your goal of gaining 10 pounds, 2 slices of pizza is not the worst meal to have every now and then. Potato chips and candy are complete garbage, so I can’t imagine they are better than not eating anything. But it’s a rare situation that candy/chips are the only things available.
I don’t do “cheat meals”. Instead, I let life situations take care of when my diet strays, and it usually works itself out and allows me to not be the weird guy eating a protein bar while everyone is having pizza.
That said, if I’m gonna workout later and the food that is available is something that will mess up my energy levels, I will skip it and be the weird guy eating a protein bar or whatever. But otherwise, as long as my diet is solid the other 90 percent of the time and I don’t BINGE on these “Regular person meals”, it’s all good. I actually think it’s beneficial for someone who is super strict all the time.