Don't listen to those barking about 3.73 or higher gears. They are stuck in the stone age ... ;). The 3.42 withe the 6 spd transmission tows better than the old 4 spd and 4.10 gear combo (hint -- check my sig ... I've owned and towed the same trailer with both!). The 3.42 and 6 spd is far superior in performance IMO to the older setup.
I think you will be just fine. We tow a heavier trailer in the Utah mountains, and have no issues. Sure, it isn't as fast as our diesel 2500 was, and we have to let the engine rev a bit going up grades, but it works fine for our purposes.