KD4UPL wrote:
You wouldn't necessarily even need a WDH with that combination. A 3500 will usually ride a lot better with a thousand or 2 pounds of tongue weight. I would have no problem towing it like it is at least until I discovered how it towed. If it turns out it would benefit from a WDH then go ahead and get one; otherwise, don't worry about it.
If he was 20 miles from home, "try it first" may be viable as you could drop off onto side roads and creep home at slow speed.
The OP is picking it up 7hr from home. I wouldn't want to be 5hr from home when I decided enough is enough...now I'm in the middle of nowhere, no place to camp and no way to fix it. Makes it too easy to do something stupid because you just want to get home.
Since the OP is planning to get the WDH anyway, buy it, install what you can before you depart and then plan on a couple hours to hook it up the rest and dial it in when you go to pick it up.