As you've probably already determined from my questions, I'm not very experienced with towing.
We rented a trailer 2 years ago and went on a 6-week trip with it. It was a 5000 lb trailer and we were towing with a '99 Ford Expedition. On paper, it should have been fine, but the actual towing experience was rather nerve wracking. I know now that I made 2 signficant errors in judgement:
1. The Expedition had 250K miles on it already and despite the towing package, the engine struggled mightily to tow that trailer. Our weights were "within spec", but the engine was not really up to the task, and we broke down in New Mexico... that's where I bought the truck I have today, by the way...
2. The rental company set up the WDH for me but did not do it properly. At the time, I had no idea why the steering was so incredibly bad. Now I know that the WDH was not adjusted properly and the front axle didn't have enough weight on it to properly grip the road. I thank God we lived through the experience.
When we hooked up the trailer to the new truck in New Mexico, as you might expect, it was night and day difference. Suddenly we had a vehicle that was way more than capable of towing the trailer, probably even without a WDH. Honestly, it drove as though the trailer wasn't even there. The only time I noticed it was when I had the trailer brake controller adjusted improperly.
What I took away from that experience was:
1. I don't ever want to stretch the limit of towing specs again.
2. 250K is a lot of miles for a gas engine to start your first cross-country RV trip towing a trailer for the first time... =D
3. Diesel is awesome.
I will not change anything until I have the trailer and see how it handles, but I still would like to get some answers in the meantime if they can be had.