So I went to Lowes Saturday mid morning and picked all of my supplies. I got (11) 5/4 Premium Deck Boards, 100 1.5" Carriage bolts, lock washers and nuts. (2) 1/4" drill bits and a set of saw horses, and a case of beer at the gas station. Got everything unloaded, beer in the fridge and music playin. Set up my first board, get my measurements and start drilling holes. I got all the holes drilled and placed the first board onto the trailer. I drilled the first hole thru the trailer and it pretty much destroyed the drill bit. This is when my BIL showed up to help. Inserted the carriage bolt, too damn short, back to Lowes.
Got the 2.5" carriage bolts, some flat washers and bought a new Dewalt circular saw while I was there, most of the boards were about an inch too long. Shoot across the street to Rural King to find (1) 1/4" bit. Hoping this one would last for the rest of this project. Turns out it would work just fine for the rest of the project. The only thing I couldnt find at either store was D rings for tie downs. I can add those later. Off to the races. Measured each board, and each hole individually since I was having to drill through the expanded metal, I had to measure to ensure I was in the openings of the metal.
The beer was flowing fairly easily at this point. After each board, we took a beer break. Not wanting to over do it. By the time we were about half way done, I had to send Chad on a beer run, just in case. Which turned out to be a good idea. So I have one board left over. I have a space for it on the end, but I will have to shear that board. I have a 2.75 gap at the front and a 2.625 gap in the rear. For now Im happy with how it turned out.
Thanks for everyones input, and thanks to Chad (Moonlab) for the help, and the extra beer.