My grandfather used to have me brush a coat of used motor oil on the wood beds of all his trailers and trucks a couple times a year. It's a little slick for a while, but it soaks in to the wood and does a nice job of preserving it. I've done the same thing to my tandem trailer bed for the 20+ years I've owned it, it sits out in the weather year 'round, and the wood is still in very good condition.
I didn't have the bucks for anything special when I built my bed, and I use the truck for hauling. So I got a 4x8 of birch-faced plywood at Home Depot for about $30, cut it up, rabbeted the planks, used spar varnish.
Absolutely correct. The width will vary with the species. In bed wood I'd recommend an oak either red or white. Let it rest in it's environment with air circulation for as long as you can- months? If it is a garage queen any finish is fine as long as you finish all sides.
You can cut the groves on the planks with a table saw, I did it for a guy last week. I'd think about using the fake deck material from Lowe's ' some sort of wood looking plastic. No rot or warping.
I thought about doing that. I don't have the disposable income to drop on a kit. I figured a good sheet of oak plywood, ripped down and sealed up good would work just as good.
I used a 2 part penetrating epoxy from the rot doctor, then man o war marine varnish over that. lasts great!
Has anyone used the product Eastwood sells? I happen to have a quart but haven't used it. If I can justify it I'm going to use 1/4 sawn white oak. After building new bed sides and front plus tailgate ,I'm not hauling anything that will dent the sides.