I have a rear swingout bumper (4XInnovations), and do some moderate wheeling with bikes on during our Colorado/Utah trips. The main issue is getting the bikes tucked in close to the truck and high enough to not get dragged going over ledges, and if they do get dragged, held in such a way as to not damage them.
Even though the bumper's receiver is higher than normal, it's still not really tall enough to get the bikes up out of danger, so I use a receiver drop adapter installed upside down - this also works to get the rack far enough out to clear the spare tire. Then the main issue is that you can't really get into the rear hatch without removing the rack - since the dropper reaches up and blocks the swingout. So that's a bit of a PITA when camping/overlanding - every evening, have to unload the bikes and unbolt the rack to get into the rear (there's a cargo platform - so to get to the stuff underneath the raised floor, the hatch has to open).
And the rack I'm using is just a simple type that has two arms that you're supposed to hang a bike on via the top tube. But modern bikes don't have nice straight top tubes - my Niner's is very curved and if I mount it the 'right' way - the front wheel drops *way* down, so I end up setting the downtube on top of the arm on one side. The plus side of that style rack is that if a wheel getts nudged or brushed - then the bike is just secured to the rack by rubber straps or bungee cords - and can fairly easily move and avoid damage.
On the Gold Bar trail out in Moab a week ago (+/- a coupla days):
Far from ideal, but it sort of works. I keep trying to think of a better solution, but I don't want them on the roof because sooner or later I'm going to run them into something. It would be nice to have a rack that holds the bikes by the wheels so it doesn't beat and scratch up the frame (putting a dirty mountain bike frame onto a rack - grit gets to grind away as you bounce along a trail).
I sometimes ponder putting some fork mounts on the rear end of the rack and just letting the bikes dangle down. Downsides to that are that out of the 3 mountain bikes we generally drag around, they would need different form mounts (QR, regular thru axle, boost), plus road bikes. And with the fork fastened firmly to the mount, if something reached up and bumped the rear wheel, something bad is likely to happen - no give.
I'm currently pondering a 1up just for the ease of use and lack of damage to the bikes - an improvement over the current rack. But I think it would need an even taller riser/dropper than I'm currently using because from the measurements on the 1up site, the rack would hang lower than the wheels currently do. Don't want to wreck the rack. Maybe something silly tall like this:
https://www.amazon.com/Quick-Adjust-Receiver-Hitch-U-4043/dp/B071R35K26
I'd still need to remove it every evening to access the hatch area, but at least the bikes would be less beat up. My wife refuses to put her CF Niner on the current rack.