Also I think the type of ramp to get can be dependant on where you live. I had one of the solvit telescoping ramps (aluminum with plastic components and the "runner top" of it was like sandpaper stuff) and it was not suited for up here during the cold winter months. The plastic broke when tempertatures get below freezing and the sandpaper grit stuff cracked and broke off in pieces as well. So I got a
Pet Step Ramp and it has held up very nicely - plus it is very very sturdy with a more "rubbier strip" type of runner material that doesn't break off when it gets wet and/or cold. It folds out to 70" long so I'm not sure what the slope would be like on your truck with it. I have a 4 runner and the slope is quite minimal so its easy for the dogs to walk up and down. A friend of mine has a Yukon and her tripod dog can navigate it very easily as well.
I got mine in Canada from Costco online and it was almost 1/2 the price of ordering from an online pet store or from the local pet stores so it was a great deal for the quality!