6,000lb dry or 6,000 lb fully loaded maximum? We towed a 5500lb 25' TT for 10 years with a 2004 Durango 5.7L Hemi.
The 2004-2010 Durango's have a very stiff frame and solid live axles. The newer Durango's have a softer independent suspension and lighter frame. Not quite as well suited for heavier trailers over 7,000lbs but should be fine for 6,000lb fully loaded. The newer 5.7L Hemi is stronger than my 2004 so should perform well. Don't even think about the V6 4.7L!
A short bed full size 1/2 ton truck with a larger engine will do just fine for 6,000lb but the Durango is much more comfortable to drive. We went with the Durango as we did not want something as big as the Suburban but still wanted a roomy vehicle.