From the photos, I think that Escape made the cabinet about 3" deeper, so the aisle is less than three inches narrower (since the door of the RM2354 sticks out). The dimensions given (31" with RM2354 and 27" with RM2454) are probably between the cabinets (not the door face to the counter), and rounded out to the nearest inch.Notice that it sticks out quite a bit, whereas the 4cu ft is completely flush. That's why the difference is 4" instead of 2 1/2" or so that is the actual difference of the fridge depth.
We have a 2015 model 17, and find that among the four of us who camp together regularly, a couple of us have to exercise a bit more care sliding into and out of the dinette. (translation: old, stiff backs)
With that in mind, the extra projection of the 4.0 frig. should be something to evaluate.