We're new here as we've only had our 3500 for a few months, but we purchased it for our family of 7 to take some epic road trips. The first trip, out to Glacier National Park, required a large amount of cargo, as you can imagine as we were coming all the way from Michigan. I already had a good car top carrier from our Sienna days and it seemed the perfect solution for sleeping bags. I didn't like the cost of an aftermarket solution and all I needed to do was fasten the car top carrier, so here's what I did: The part list is: 1 1/2" galvanized pipe strap - Qty 4 1/4" hex bolt, 1" length - Qty 8 1/4" hex nut - Qty 8 1/4" plastic washer - Qty 16 Total cost = @ $9 (car top carrier was $100 or so, but had it previously) I cut the bolts down about 1/2" for length purposes, as they were a bit too long and put a washer on each side of the frame. I tightened with a 7/16 socket and a 7/16 wrench to hold the other side. Here's the final product: I could have used something stronger than the pipe strap, but I had a few laying around, so just went with it. They bent a little bit, but nothing major and we made it 4500+ miles with it on there and no issues. They are removable, which is nice, so I don't have to keep them there (because my wife doesn't like the look of them). They will probably go back on when I attempt to hoist a Christmas tree up on top of the monster this winter. I might have missed something in this post, but thought it might help someone else out that is looking for a cost effective solution.