Off Road Trailer

I have 2 trailers to pull behind my mowers, a Craftsman Hard Top Tow Behind Lawn Vac that i removed the engine from but still have it if i ever want to use again, and the other trailer is one of those 4 wheel monster carts Tractor Supply use to sell. The second trailer is big and i use it all the time for hauling riding mowers. The second trailer is great and i have no complaints about it the first trailer i would like to make into more of a off road trailer that i can use to haul stuff out on the trails with me like tools, parts, spare tires, gas, all that stuff. It is big because it is really just a lawn cart with a big ol metal roof on it and it has a super long tounge that i want to put a toolbox on. Yes its a really long trailer but its not going behind me on the trails per say i will take it around and part it where my little pit stop area is and just use the tractor by itself for the trail riding, i will have 2 tractors with me, one to ride and one that hauls everything and pulls the other out when stuck lol. Anyway this lawn vac has a homemade tounge on it that somebody definetly went overboard with its made from really thick and really heavy C channel and square tubing. Now does anyone have any ideas or suggestions for my cart? Heres what i have in mind. Plastic or poly whatever its called box on the tounge to put crap in, gas can mounts on the front part of the bed, bigger cart tires, and i am thinking about putting like a big shelf inside the bed so i have more ways to put stuff in. Its going to have alll the parts i would need, 2 spare tires for the mowers (1 front 1 back) and 1 each for the trailers, also gas, oil, grease, tons of tools, and maybe instead of a poly tool box on the tounge i may put a genorator, and a small air compressor and MAYBE a small welder if i could ever find one small enough, i mean i want to be able to fix any problem i may have. This trailer is gonna be super heavy but i will pretty much be bringing my entire garage with me when i go out on the trails.

I have an idea for walking tandem wheels for this thing Ok i got my lawn vac thing and i dont need the vac right now so i took it off and im thinking about making the trailer a little more off road-able and i want to put tandem walking wheels on either side. I was thinking just keep the stock axle and make a tandem setup that slides on like a wheel. I was thinking about taking some square tubing and using a peice about oh i dont know 2 feet long i guess and right in the center put a hole in it and weld a pipe in there and put bearings in it or just a pipe with grease zerks and then on each end of the square tubing put a axle on it so i can put 2 wheels on it and have 4 total wheels on the cart and these would stick out further making it more stable and i can put taller tires on it which would hit the bed with the stock set up. Well what do yall think?