I've always been a 1/2 ton Chevy guy but IMO pretty well any of the current 1/2 tons with a V8 or ECO V6 would easily handle a travel trailer weighing 6000 lbs loaded. Vehicles have come a long way since your 2002, both in engine and transmission capability - indeed even my 2012's 6 spd tows better than either of my earlier version 4 spds. I'd look for as much payload as you can get and pay attention to the axle ratio, 'cause even with a 6 spd or 8 spd a 3.73 axle will still be far more capable when it comes to towing than say a 3.21.