Awning Pulling Gutter Away from RV -- Best way to ReAttach?

I'd try to determine *why* they are pulling away before doing a fix. It is possible that water is getting in there, making the wood behind it go bad. then, as mentioned, if the wood isn't bad, you may need to use bigger screws, or use something to get better bite. Finally, I'd be using silicone or similar both between the gutter and the trailer wall, followed up by a bead of it along the top, after its all in place.