Well, FWIW, I just towed a Nash 25c (rental), with my ML350 diesel, from Seattle to Yellowstone. Probably just a bit too heavy IMO (5700lbs dry), probably 6600 wet, but no issues. Kept it at 60-65mph the entire way, only place we had to take it easy was up the continental divide (long steep uphill on I-90), was having trouble maintaining 60 and had to drop to 50-55. Was the first time, and only time I saw my engine timepiece rise...the 90 degree weather probably didn't help.
Trailer sway was kept under control with an equalizer 4points hitch, and the MLs trailer sway program, which worked really well, using AWD and brakes automagically to cancel sway. All in all, I discovers a few things:
The ML350 diesel is an awesome tow vehicle..Getting 14mpg towing a 6500lb+ trailer is impressive any way you cut it.
The Nash is not a great fit for this car, heavy, old fashioned wood construction, lack of aerodynamics, bouncy, high suspension, made it ride a bit too "truck" like. I'm now looking for a lighter weight trailer, with better aerodynamics, lower, more modern suspension and build materials.
Power wasn't an issue, and the Tenkosha Rf brake controller worked flawlessly.
