I just enjoyed a road trip in a new 4500 from Indy to Arkansas and back. I had several reasons for the trip including working with the folks at the AR plant and bringing back some new equipment for customer installation.
Beyond that a good reason to exercise and enjoy a new service truck. The truck is a 4500 with custom bed including boom, heavy welding equipment and 4 huge (and full) tool boxes. Cummins diesel, Aisan (sp) transmission and 4.10 rear.
What a nice truck. I drove down to AR, loaded around 7,000 lb of equipment on a 24' flat trailer and made 625 miles in under 10 hours coming home... heavy rain, traffic and construction not withstanding. I was probably grossing ~25k lb and that was no bother at all. Not a lot of hills but the ones I did encounter I pulled in high gear as long as I was rolling at the start.