Just a quick word of advice on this build is keep an eye on your axe and spring weights. We all want a pit but we also want it to be safe especially if you are planning to actually tow this on the road. I can see in your posted pictures that your leaf springs are squashed flat and your firebox is not mounted yet or your end cap stacks or grates let alone any small parts you install you are looking at a minimum of 200+ lbs. before you get wood on there. I say this because I've seen the effects of overloading a trailer in tow and it's not pretty.
I would seriously have it inspected by a trailer mechanic before taking it on the road. Just my $.02. Now carry on!
Cooking for the love of it.