I need to know how to make my 2004 chevy silverado with 6.0 pull my travel trailer without struggling. I have 35's with a 6 inch lift. I have heard I need to upgrade my exhaust, my gears should be changed out to 4:56 gears and I need to upgrade my torque converter. I'm not very mechanically inclined so I would probably have to have a shop do this but I need to know if I am asking for the correct upgrades. I also want to get better fuel mileage because I pulled my camper to the lake which was only like an hour away and it burned almost 3/4 of a tank of gas. Please help.

 

everything is a compromise...you can't have it all...every mod you have added works against what you are trying to do.
exhaust upgrade would be a complete waste of money imo
35 lowers your gear ratio so you lose at least 1000lbs off the tow capacity
6 "lift ;aero wise wrecks mileage
4.10 is good ratio. if you have that leave it and put up with the mileage. You can't change physics.
3.73 kinda sucks but your into $6g to change out both front and rear diffs...4wd? that buys a lot of gas.