I've got a 1/2 ton AD bed trailer, just started using it to haul firewood.
Someone else made it and used a newer axle looks like a rear tube axle from a front wheel drive vehicle cut in the middle and welded to the right width.
Problem with the whole thing is weight distribution, even if I stack two rows of firewood in the very front, and double high, with nothing in the back 1' of the bed the trailer still has very little tung weight.
The empty trailer probably has 30 lb tung weight, if that.
So if you can always haul something in front of the axle it'll work, but if the weight is at or behind the rear axle could be difficult and dangerous to tow.
I'd suggest buying or making a more normal trailer and use the truck bed for a truck, or sell it.
I bought the one I have for the near perfect fenders, but figured I'd try it as a trailer to start with, it works but not very well.
Grigg