If you are near a trailer dealer, you may check to see if they will loan some keys to you to try. I think these cheap RV locks are similar, even the dead bolts. I had a key on my truck ring, I thought was for my FW, and used it to easily open the double locked door. When I grabbed the camper keys later, which has 2 separate keys for the door, and of course the 751 baggage key, I realized the key I used earlier, was for the side RV type door on my enclosed snowmobile trailer. Comparing the keys, pretty similar.
You just need a key from a dealer that works well, copy it, buy it from dealer, if an extra.
Jerry