Our 25 footer (26 bumper to bumper) on the E450 seems to be the sweet spot, to me. The 182" wheelbase helps. Not a lot of rear overhang to drag on driveways or gas station entrances. OCCC of 4,209 lbs. We take along all we need, for weeks at at time. Typically carry 1/2 tank of fresh water. No chance of it ever being overloaded.
I had a front end alignment when it was new and loaded for travel. It has been smooth as can be from that day forward. No handling issues, even in pretty high wind. Blow by from big trucks doesn't bother at all. I'm comfortable driving it all day without arriving at the destination worn out.