The best tonneau cover for what you are planning is the BakFlip. They have several models made to fit each brand. I've had my G2 for several years and love it. It will fold all the way up against the cab when I need the entire bed. When hooked up I fold mine one short of all the way and it clears the pin box even at 90 degrees. It also covers my generator, gas cans and tool box so they're out of the weather.
When not towing it closes all the way and I lock the tail gate for security. It's hard top and only seeps a little in some areas...not a problem. Check them out here.