This project was inspired by a trailer I saw online. I just imitated the design for the frame and really cheaply. I bought a couple sticks of electrical EMT conduit along with (4) 90 degree bends, and welded it to form a box. I got two 4" angle brackets, cut them in half, and welded them to the frame rails for wheel mounts. Mounted the flatbed with (6) single conduit clips. Then I fabricated a swivel joint to connect the hitch on my Schwinn El Camino.
viewtopic.php?f=21&t=69825 Painted it black and added some vintage 20" rear fenders & braces.
(1) I can use it as a flat bed...
The wheels are quick release, and the tow bar is bolted to the inside of the frame and is removable. For storage, the whole thing with the exception of the wood box comes apart with just a few bolts.
(2) Add the box I built ( inspired by pick up truck side boards) with a tailgate for my cooler or dog...
(3) Bolt on one, or two steel car top carrier rails to haul my other bikes.