How do you build an off road trailer?

I am new to this hobby and am getting project mower soon (hopefully). I would like to see some other off road trailers people have built to get some ideas. I need something that can hold up to 350 pounds, and be capable of off road use without dying. I have seen one on youtube I liked, but it was too short of a video for him to explain dimensions, helpful mods, etc. I already have a project trailer. Here it is:Project off road lawn trailer By the way, the heavy piece of tubing in one of the pics was installed. new wheels+tires were installed. Everything else is the same. Anyone out there got pics or ideas??

this is fearless fronts trailer.
https://www.youtube.com/watch?v=fBTxwoHjV88

I made a small trailer to tow behind my mountain bike out of plain steel angle and 1" thick wood , used a 1" steel axle and wheelbarrow tires , just to haul a boom box and cooler for picnics - i over built it pretty darn good .


Id say even a regular dump bed trailer from harbor freight would work, with a few mods.

If its for weight/offroad- atv wheels would be the best - either with a moveable suspension ( to crawl over rocks, ect) , reinforced floor , trailer ball hitch ( swivels easier ) and definitely get wheels with berings so they wont give any issues.

My partner and I are building two from a 55gal drum..
It'll have two wheels probly old front tires and rims from a mower..basically a T shape lower support welded in place..
Simple but since it's steel you can add to it by welding and such..
I'll be posting a video soon of that when deer season gets closer

just use a dump trailer from homedepot, thats what im doing, so then u can haul dirt and stuff for yard work too