Hello everyone. Newbie here 2/15/20. We just purchased a 2000 DRWRWD, Crew Cab, 8’ Bed, 4:10. This truck is bone stock and never been chipped. One owner, meticulous records (all good ) just turn 137K miles. We are now shopping for a 5th wheel camper. I understand all the weight calculations. My question is, what is the max RV weight that we can pull down the interstate with the cruise control set on 65 and set back and enjoy the ride ? Knowing that pulling the one also has a high wind resistance that must be considered. Thanks in advance.