The same thing happened to us too. we got 1 key that only opened the small travel door. We thought that key was all we needed. After we got home and tried the key in the screen door and small compartment we found out that we needed 3 different keys. Called the dealer 2 times and they said they would send them, but they never did. so I bought a new screen door lock, and put that in. I guess I could have taken the lock to a smith. but figured that would have cost about the same as a new lock. As far as the small compartment door, that's a 751 key, so we bought a couple of them.
2013 Rockwood popup 2318 g. TV 2003 trailblazer and a 2013 SLE Sierra p/u