A couple of suggestions, put your tool box close by your work table area. When placing your welding machine, make the dials easy to reach also from your work table area. Most folks with rigs work off the back end rather than the sides (dont want to get that hot metal near the tires). Mount your vise on one side on a small extension so it sticks out past the side so you can spin it and put long pieces in it that pararell the trailer. Use a good heavy bumper that you can mount the vise or other tools to without damage. Perhaps even mount an anvil on one side or use railroad steel for th bumper so you can beat on it to straighten things. If you really want to get fancy, built reels to roll up your welding leads and cutting torch hose, at very least build a roll up rack for each lead and cutting torch. I used to make a rack for the cutting torches that hung on the oxygen bottle that when you took off the gauges, you laid them around the rack after rollin up the torch, then just lifted the whole thing off the bottle and it was ready to go. I did the same for my TIG rig> THe whole thing is just a ring of 3"pipe about 3/8" thick to fit over the bottle top, weld your tubing or rebar to the ring, come out half the diameter of the bottle, 90 down about 18-24". build to and bottom stand offs that contour to the bottle diameter you use, then directly opposite weld on an L shape with the bottom of the ell about 6" long and the top just long enough to accomodate all your rolled up hose + about 2". They fit nicely in a 36" JOBOX so you can lock them up
