In long trips i.e. over 3 hours long, I take some toasted break with either pb&j or something inside e.g. slices of turkey etc (toasted). I wrap them with aluminium foil and place them inside those transparent food bags/freezer bags we use to for placing items in a fridge. The problem is that the toasted bread becomes very soggy. Is there a way to prepare/wrap/store them that would be more fresh after few hours? 
As has been stated, you are trapping moisture vapour. I don't think it is possible to perfectly preserve the texture of toast over a prolonged period, but you will improve matters by letting the toast fully cool before you construct your sandwich. Edit: when cooling your toast it is helpful to prop it vertically rather than lying it down as the underside will still get soggy. A toast rack is the perfect way to do this, but you can also just prop the slices against each other like a little tent. You may also consider wrapping your deli-meats and any salad items separately and only adding them to your sandwich when you are ready to eat. Mayonnaise will also tend to make your toast soggy, particularly if you use a low-fat version with a higher water content. Butter/spread applied when the toast is cold should only have a minimal damping effect. 