I tried this and I can tell you a few things by looking at this
First, the trailer has too many wheels and will instantly wipe-out. It can only have back wheels. Also, use steel bushings in that truck LoL.
Second, you have to put the battery under the deck or it will immediately flip over unless your hinge mechanism prevents that, in which case it’s jerking and pulling your back truck and trying to wipe-out the front board.
So you have to use huge wheels and the center of mass needs to be under the wheel axle. And only use two wheels in the back that don’t steer.
The trailer I made, I took apart again because it wasn’t practical.