Have Fifth Wheel--Will Haul Bikes
For us, hauling a couple of bikes meant a front-of-the-truck bumper mounted bike rack we picked up at Camping World. In order to have clear visibility from the wheel we'd take the seats off the bikes, otherwise those 'rump cushions' were right in the line of sight. Yes, you had to put up with bugs and dings on your bike, because if you covered them with a protective bag it obstructed cooling.
Other fifth wheel folks put racks on the rear bumper of their fifth wheel--provided their bumper design allows for it. Some fiver manufacturers forswear this by warning that nothing should be mounted to their particular breed's bumpers. A possible response? Add a hitch receiver to the trailer frame and use a hitch receiver style bike rack.
Some we've seen get what looks to be way out. They weld a hitch receiver to their fifth wheel hitch on the trailer and carry their bikes right out their leading their fifth wheel's front cap. Wow! It must be a real picnic to balance yourself on the pickup bed and manhandle your bike up on that rack, but hey, if you're a dyed in the wool biker, you do whatcha gotta do.