I still fail to see the problem. A tow dolly and car combo is no longer than a car and tow-bar. The only thing I can see is that a Jeep type vehicle will handle rough ground better than a car dolly. When you consider that all PHEV's will have the battery underneath I would suggest that towing either in rough ground may not be a good idea.
I am not saying PHEV's are different than EV's like the Leaf, only that the advantages as they are right now don't lend themselves to the posters requirements very well.
I don't have a citation for the quote about people not plugging them in, a valid critique, but have read it somewhere, just don't have it at my fingertips.
The Poster had said he was happy with his Leaf but was thinking of downsizing to one car and a RV and lamented that he couldn't find a PHEV that could be flat towed.
Rather than replace the Leaf he is happy with, for the 1-2 long trips he takes a year, and not being able to find a PHEV that could be flat towed, I suggest holding on to what he has, and solutions for the two "problems" that caused him to look elsewhere.
My situation is I can't make it to a car rental and back on a single charge, I am and was aware of that when I bought my car. If I get a 40 KW batttery installed, I could, and eliminate one of my ICE vehicles and rent a car for my few long trips and still be money ahead.