THIS^...manual should be the guide, I tow in 4th (Tacoma) w/ anything over 1,000 lbs., on a RARE occasion I'll slip into OD on a decline/level, 4th on any upward incline...Read your owners manual. Varies by vehicle. My Tacoma manual says not to to use cruise.
Well, some of us on here are licensed auto mechanics, (since 1987 in my case), so I guess I would call my tip a pro tip.What you should have noticed is that nobody with advice here has the same setup as you do.
No pro tips just other personal experiences with a variety of different vehicles.