I’ve been making pizzas on the go with a portable pizza oven and it’s been going really well but sometimes if I don’t time things right I’ll end up with huge seemingly overproofed doughs that become harder to work with as they keep rising. When this happens should I knock them back down again and let the dough proof again in the box?
Over-proofed dough can be saved. So, if your dough is truly over-proofed. Degas it, reshape it (in a ball for pizza), and allow it to proof again.
What must be happening is that your dough that is waiting while you model the others in the shape of pizza, is getting dry. If you keep the dough well moisturized should facilitate your handling, I advise throwing some water using a spray in the doughs that are resting while you work with the others.
It depends on your dough type and recipe, but I personally don't find somewhat overproofed pizza dough to be a major problem. Just pop any large bubbles as you are stretching it and handling it, but otherwise just bake it normally. I frequently overproof my pizza dough on purpose, as I often like the resulting flavor a bit more.
If the size and number of bubbles in the dough still gives you an undesirable result, you can either knead the dough slightly and proof again (as OP suggests), or you can be more aggressive about degassing while stretching the dough for pizza, perhaps employing a rolling pin.
I'm not sure precisely what "harder to work with" refers to in the question, but overproofed doughs can become dried out (if left out) and harder to stretch or more sticky (if kept in a humid environment). The remedy for the former is just to cover the dough while you wait; for the latter, just be sure hands and surfaces are well-floured. The last thing that sometimes happens is that overproofed dough can become very slack and less elastic, making it stretch very easily and perhaps tear. In that case, only gentle handling is typically needed to stretch the dough. Rather than tossing the dough or handling it roughly, all that is often needed is the weight of the dough itself to stretch itself over ones hands. Once it becomes thin in the center, lay it down on the surface where it will be topped, and just stretch out various sides farther as needed. The resulting pizza may not be as perfectly round as a tossed one, but it will usually still bake fine.