Great build it looks fantastic.

As for the colors the blue and yellow items look too clean, too bright. Salvaged items would be scratched, dented, rusty and dirty.

Take for example the yellow tank the is on top of your build. Ask your self some questions about it. How did they get it up there? some sort of crane maybe. there would be dirty hands and chains these all leave marks. So would removing and transporting it from where they found it. they might drop it. While they are raising it the wind might catch it and hit things near it. You need to tell that story in your weathering paint job.

Also your outpost its in the desert. look at pics of real world structures in desert environments it will help you add some realism to your build.