Cruise Control/Tow Trailer Mode

I have a 2014 Ram Express with factory tow package, it is a Hemi with 6 speed tranny. This is the first vehicle I've ever had with a tow mode and cruise control So I'm wondering if you can use the cruise control while you have the truck in the tow/haul mode. The reason I would like to use the cruise along with tow mode is I'm having a hard time keeping the truck under 70/75 when pulling my 2 horse trailer. I never know the trailer is back there unless the horses shift there weight. I'm thinking that I should have gotten the 3:92 gears in stead of the 3:55 maybe then the truck would have been happier at 60/65. She wants to run at about 1800 to 2100 rpm on flat ground which is going to get me contributing money to the state. So what do you more experienced Ram owners recommend all help greatly appreciated and thanks. Carol