Have you weighed your truck and trailer at all? If not, consider weighing it when loaded up for a trip before going forward with the a-frame bike rack set up.
Weigh 3 times.
1: Truck and trailer ready to roll down the road. WD bars latched up.
2: Truck and trailer, but unlatch the wd bars. Place them in the bed.
3: Truck only. Leave WD hitch head in and bars in bed.
This will give you the loaded tw if your trailer, rear axle weight, and let you know how the wdh is adjusted. And let you know if your truck has enough payload available and the rear axle weight has enough "cushion" left for the a-frame rack.
Does your trailer have the tabs on the frame, at the rear just before the bumper? I added the factory Jayco receiver cargo hitch to our 32. I bought the hitch stabilizer u-bolt kit to eliminate the rack from bouncing as much. From what I understand it does pretty good going down the road. I have a thread in the Mods section that has pics of the hitch, and I believe the bike rack we have also. Also have pics in my signature link.
Some bike racks are not stout enough (rated) for the back of a tt.