I'm assembling a "box" for my equipment trailer to ease transport of household items.

This pic shows the rails I put up to aid in transporting firewood, mulch (with a liner), gravel etc.
20140807_120053.jpg

The 2x6 horizontals were put based on the max load of stuff I could carry. However, I need to remove all to load one of my tractors.
m4700-trailer1.jpg

I've now put 4' high plywood sides and a roof on, all wood is either plywood or 2x4's. My primary fasteners are 3/8" hex bolts and flat U bolts of varying lengths. One of the main features I was focusing on (besides safety and rigidity) was ability to assemble/disassemble it by myself with minimum tools. With a battery powered drill spinning off all the nuts is relatively quick and easy until I put the top on.

The drawback is that on the hex bolts I've got to "clamp" the nut on one side to bolt/unbolt while ratcheting the other end . When assembling the sides that means when it is enclosed there are a lot of trips to 1) put the bolt thru the hole and clamp visegrips on the head 2) go inside put on washer and bolt, tighten 3) Repeat

This requires a lot of trips in/out and up/down the ramp (or a lot of vice grips to hold the bolt head outside. Without clamping one side of the fastener they will just spin. So I'm going to try T-nuts embedded inside so I can just put the bolt in and screw it in.

Which brings me here - is there an alternative to T-nuts?
And - can people recommend a good reference graphic to show ALL different type of nuts similar to pages like http://www.zoro.com/s/?c=4388&cn=Nuts&page=2 , or http://www.mcmaster.com/#nuts/=u6dxvr , so I can print a graphic for my shop, and provide a link.

thanks