I have spent much of my weekend modifying or changing the drawings of my bus. I like an open feel to the interior but am having a little difficulty with isle width in regards to my dining booth and counter.
An "open" feel is based on the top half of any enclosed space. This is why so many apartments and condos are designed with a big opening between kitchen and living room. Your eyeline is up near the ceiling, not down where the chairs and table are, so that 26" will work for you, especially if you have a lot of windows to let in outside light.
Visitors to my coach comment on how open it seems, even though the luggage racks are still in place and the aisle through the front room is only about 24" wide, because I have left all of the original windows -- light comes in from every direction, and with the drapes open, you can see the landscape.