Without totally ripping the
Without totally ripping the trailer apart and removing every shred of fiberglass insulation, there is no way to treat every possible spot, especially in areas where there are rather permanent structures. (shower stall, refrigerator cabinet)
I'll just get out what I can get out, spray what I can spray, and make due with whatever is left. As soon as I can move into my home, I'll rip the whole thing down. (maybe utilize the frame for a portable saw mill) Actually, in hindsight, I could have done better by buying (another) reefer trailer, and salvaging the appliances, windows, bath fixtures, etc, and making the reefer trailer into living space, and probably had it done in a shorter period of time/money that the course I ended up taking. But that's just typical hindsight.