My understand is the 2005 was the last year Honda gave towing instruction in the owner's manual. The 2006 and later years Owner's manuals indicate they can't be towed.
I understand the suspension system was changed, as well as possibly the transmission, which won't tolerate towing. Also, some owners of the 2005 and earlier models complained of frame weld failure problems, possibly due to the strain of being pulled around. A Honda dealer's salesman told me in 2006 that the 2006 model was towable, and they would just quote the 2005 manual. So, so much for salesmen. (I also didn't buy a Honda, but a Hummer, which can be towed.)
Wish I knew more and had specific facts to quote, but I don't.
Holiday Rambler Navigator DP, Hummer, and Honda VT1100C Shadow