How often are you going to haul rocks or appliances in your truck? You said you have a trailer so I'd put the big bulky stuff in there. I've got a topper on my truck that I take off once a year when we go to Oshkosh and need to haul bikes, generators, gas cans, etc....
The rest of the year the topper stays on and it's great. Getting the topper off is no big deal, 4 clamps, one plug and then with the help of my kids or the friendly neighbors and a beer or two, it's done in 15 minutes...
I had a tonneau cover for a couple of years, looked cool, but if you hauled anything higher than the sides of the box, you had to roll it up and everything was exposed to the elements again. That and the Velcro seals on the sides started to wear out and the top would get loose, flapping in the wind. Totally lame! No regrets with the topper, you can hold a lot of stuff in there when going on vacations, trips to the see the family over Christmas, etc...
I've got trailers to haul the rocks, messy items, furniture and the like. If weather is an issue that might effect what I'm hauling, well then, I wait it out if wrapping won't do or haul the item at a later time....