You can kinda trigger those hideouts and defend the camps too by just doing something different. Looks a little like the game notices you're busy and wants to nag you by spawning them
For example ride to a place near one of those campsites and go fishing. Not just only picking up the fishing rod, you really have to catch some fish. Usually doesn't take long until the event spawns.
But consider those events have a cooldown time too, after you finished one you can't just go back fishing and wait that it spawns again. So better try this in an area not many other players are active (quick travel).