blw2, perhaps most buyers now assume a living room slide as a given. I've seen opposing slides in living rooms that leave a center area too wide to be called an aisle.
Anyway, I agree that in smaller motorhomes like an Axis/Vegas that only have one short +/- 6-foot slide, that a comparable floor space (square feet) would only be a foot or two, but on larger units with more slides it would be a lot more. I estimate it would take at least 5-ft of extra length. And other than making driving and parking more difficult, an extra 5 feet of length gives a lot of floorplan flexibility too.
Closer to my interests, comparing a narrow coach like an Axis/Vegas that is 94-inches wide to a wide-body motorhome at up to 102 inches in width, the difference in interior width is about 8 inches (ignoring slides for now). So that would be like comparing a 27-foot Axis to a 25-foot wide body (thinking Winnebago model).
While the extra width would be great, what do you eliminate along the length to make up 2-feet on either side? Or do you save length by using a corner bed and corner bath? That's just one example of how designers save on length.
Personally, I hate corner beds, so if that was required to give me a little more space in the living area I would take the narrower MH.
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