Funny that you mention that, since I first wrote RV before renaming it to small bus. I doubt that it is a motorhome: too many/big windows, and the door in the middle looks very "bus".
I can't remember if the 26 meant it has a 2.6 litre engine or 26 seats, but I think it was engine size, as later Mazda buses were called T-3500s with 3.5 litre engines