Well guys. My 30 foot Apex is 4811lb dry, and a little less than 6000lb loaded ready to camp. It is now 2017. Not all RVs are made with heavy wood laminate or Metal sides. SOME of the better units are made with light weight composite material, that is not only stronger, has higher insulation values, is lighter, and won't rot.
So it is more than a little possible the op has a 6000lb loaded TT. Also he has a 1500 HD which has a higher GVWR than a regular 1500, and with the same engine, and rear gear as a 2500. He will be fine.