We noticed that the long overhang lends a lot of jiggle to ours on our first trip and having had stabilizers at the rear of our previous 5er (shown below) had to do something quick
so I too did the simple approach -
northern tools had a hand crank 2k jack that I place under the rear hitch and tighten it up...
helps with the jiggle,
but true outrigger stabilizers are needed to stop the slight side to side we still get...
just lost all interest in improving anything else until the issues are resolved...