I am sure a DP would be even better, but I moved from a 14 year old Damon Daybreak to a 2012 Newmar Canyon Star 3920 on a Ford 26k lbs F53 chassis. What a difference. I have yet to notice a truck passing me.
I haven't even applied the "cheap fix" talked about in the Ford Chassis forum, but many say that improves it even more.
Since there are no new toy haulers with diesel engines, and the used ones are very hard to fine, gas was the only route I could take, but quite happy with the improvement. (Now just hoping my second engine lasts more than 4k miles.