The trailer looks like a late 1963
26' Overlander or longer Airstream. The 7 panel rear end with tail lights on the outer curved sections indicate is it a 1962
California built Airstream. But the stove with oven door glass and the countertops & moulding were used beginning in late 1963
(and throughout 1964), so those tell us its a late 1963 Airstream. Its hard to gauge how much of the old trailer has been cut off forward of the galley, hence 26' or possibly longer. A classis "bread truck" Airstream before its time!