I lock out overdrive when towing, since I have the 4.3 in my Silverado, there's no chance I can pull in overdrive without lots of gear hunting. 3rd gear at 60mph is 2600RPM, which is almost right at the torque peak of my 4.3, and it tows great there. I also typically don't use cruise, towing or not. My first car that I drove for four years and 80k miles didn't have cruise, so I just got used to driving without it.
Towed: 2009 Rockwood Mini Lite 1809
Tower: 2009 Silverado 1500 2WD 4.3 V6
2016 Camping Season: 34 Nights, 6,811 Miles