GM 2500 and TH owners

I have a 2002 Chevy 2500HD 4x4 extended bed with a gas 6.0 motor and automatic transmission. For almost 8 years I carried a Lance camper that weighed 3200 pounds wet but was probably closer to 3500 most of the time. If you go by the sticker and take all of the other passenger weights and add to cargo I can carry 3200 pounds, tow max is 10,200. I also had bigger tires to allow for the extra weight. I would struggle up hills going as low as 45 but not running the rpm's high. MPG as low as 7 but often around 10. We just sold it in December and now I have a hitch pull toyhauler that has a max weight of 9980. I went back to stock tire size to hopefully regain some mpg. We went out over New years weekend nearly fully loaded and I could climb at 50mph but again, not pushing the rpms all the way up. Mileage is ranging from 7-10 still. I hope this helps you in your questions. It is a great truck but if you have the option for something more powerful you should not hesitate. I would not attempt to pull a 5th wheel with it.