What you need is a good one-step camouflage spray paint.

Ignoramus322 wrote:
I have this trailer that I made with a military surplus bed.
....

A bigger question is what to do on the outside. There is a lot more
paint left on the outside and I sort of like the camo color
pattern. (though the grey color is not bad also and would fit the
color of my pickup)

Ideally, I would like to find a way to mostly preserve this pattern. A
few months ago, on the spur of the moment, I bought a couple of little
cans of paint at the local pro paint store, but I am a little doubtful
that latex paint will really adhere. Does anyone hve any experience
with repainting with latex over old paint or wirebrushed rust.