Cruise Control While Towing?

I tried the cruise control once for about 30 seconds.  I quickly turned it off.  

On our very first trip - home from picking up the POD - I learned not to use CC. The engine would kick down to 3rd gear all the time and I saw I was getting about 7.5 MPG. The LR3 has a manual shift option. I quickly learned to use that and mostly keep the beats in 5th gear, in 4th up some hills and occasionally in 3rd when needed. At a highway speed between 60 and 65 I now get 12.2 - 12.4 MPG. My tach is my shift guide.

We only use c.c in the open country when the roads are flat to gently hilly, otherwise we use the pedal.  As others have already stated, the engine is constantly searching for the correct speed and the tranny is constantly shifting as well to accomadate the engine rpm's.  

We've got a somewhat modified 182G and tow with a newer Acura MDX.  I don't use cruise control in the hills, but I've found that the adaptive cruise control is awesome on the flats... especially in heavier traffic.  It uses radar to range the vehicle ahead of you and maintain a constant distance.  What a difference it makes on HW 5 in California.  I set the car for 57 Mph, and just steer.

WE have a 2003 Toyota Mini-van.
On our recent 3800 mile trip from Seattle to AZ and return, I used cruise control on the flat stretches.
Worked fine.
I turned off overdrive whenever the transmission downshifted.
The Toyota's V-6 was a champ. Handled the 6-7 mile long mountain climbs very well.
I drove conservatively, but ended up passing semis on the long climbs, just because there was no reason to slow down.