I have a Leer cap. Do not have a cargo slider. Would be nice though.
To help with reaching stuff in the front of the bed, I use those tubs sold by Lowe's or Home Depot for mixing concrete. They are pretty strong. I fill these tubs with generators, extra gasoline, air compressor and floor jack, and other stuff.
I shift them around by using a garden hoe. Hook it over the edge of the tub and pull it. I'm mostly using just two of the tubs, the one with the two gennys and the one with the extended run gas tank, plus the extra gasoline containers.
