I recently pulled my travel trailer from OK to Charleston, SC and back. I never drive over 65 MPH for safety and MPG reasons. I always stay in the right hand, slow lane except if I have to take a left lane exit. Since I was always driving slower then everyone else, not once did I have to hard brake. Tailgating is a choice and a dangerous one.
I was never honked at, even by the crazy semi truck drivers.
Because you were towing a camper and "slow and in the right lane" fits people's mental model of how recreational/nonprofessional heavy traffic or otherwise "handicapped" vehicles ought to behave.
When you have problems is when you behave to a standard beneath what other people expect from whatever kind of traffic you are.
I don't want to live on this planet anymore.
Setting the side mirrors based on the AAA method works for a lot of reasons, and it helps with this too. So does flipping the center mirror over to the dark side.
Out of sight, out of mind.
They can be elect to stay back there behaving however they want, or they can go around be however they need to be somewhere else.
If you just can't stand it anymore, then just hop off the highway. It can be a good opportunity to stop for some coffee or a soda. Or, you know: Just to get out of the car, stretch out the ol' legs, and taste that acrid city air, think about something or someone in the world that is beautiful for you, and chill down a second.
Or just go up one exit ramp and down the entrance ramp on the other side of the crossroad, if the intersection design allows this move to be made safely and conveniently.
They almost certainly won't follow. They'll instead be disappearing down the highway at warp speed the whole time you're doing this, and you'll probably never across them again in your entire life.
It only costs a few minutes. They may seem interminable, but they're few. The benefit is relief from the mounting agony of dealing with this aggressive driver that might otherwise stick with you the rest of the day and that's good for your brain health.
(And if they do follow after you give them every opportunity to not do that? It's not Hollywood or the national news and this actually doesn't happen much in the real world on an individual level, but: Call the police at 911 or 999 or 0118 999 881 999 119 725 3 or whatever it is, and get some help.)
So much of road etiquette boils down to leaving adequate space so others can maneuver around you. Trying to optimize your travel by destroying any gaps as soon as they appear actually has the opposite effect.
However, on the rare occasion I've found myself going slowly in the right lane, it's stunning how incompetent most people are at merging. It's like they don't even consider looking for an opening in traffic, matching the freeway speed, etc. They just lumber in front of you at 43mph, and maybe, if you're lucky, look in their mirrors after they've already caused you to slow for them.
Speed is a very dangerous thing when pulling any type of trailer and it always amazes me when I see a truck pulling one at break neck speeds and somehow thinking they can maneuver normally when someone causes a situation where they have to make a split second decision.