I am using a post WWll civilian 1/4 ton Bantam trailer to haul my PA and my son's OB. I already had the trailer and it has 12" of ground clearance to get into high Sierra lakes on 4x4 roads. the racks are nothing more than black pipe that are screwed into a mount that fits in the existing pockets inside the Bantam trailer. the PA is sitting on Yakima mounts and the OB on top is sitting on two foam blocks on top of the PA. the only problem is lifting and removing the OB up onto the PA since it is so high. the yaks sit high enough so that if I am rear ended the trailer will take the brunt of the force (sure hope this never happens as finding a decent Bantam trailer is not easy). I might add a third rack to the middle to help support the heavy PA with the OB on top of it. I have switched the original Fulton ball mount that was worn, noisy, and unsafe to a Max Coupler that articulates on three planes, great for off road travel.
when I first bought the PA the kid that helped me load it on the trailer insisted I should carry the PA upside down. he strapped the PA too close to the pickup and the first driveway I went over the front of the PA put two dents in the tailgate and scraped the paint on the bed lid of my new Tacoma. I should have listened to my gut instincts and strapped the PA the way I wanted to. I have since gone to slightly taller risers on the pipe racks to get more clearance between the pickup and PA especially in off road travels.