Slim chance that someone here had the same 31+ year old RV and will see this thread, but those boxes usually aren't TOO hard to find if you are looking in the right places. Maybe in a cabinet or closet, look for an access door like cavie mentioned. Under a bed, if you have storage there. Another tricky place for items to be stored is under an interior entry step, although that's usually a motorhome thing since they have a couple steps outside and a couple more steps inside (versus trailers that are more likely to have all steps outside).