In case anyone ever wondered...we brought a window A/C unit and stand with us but never ended up needing it!!
Our trailer stayed COLD the entire summer last year! We have the upgraded, larger A/C (15k BTU), insulation and the enclosed belly. Also, I added heavy thermal drapes and used Reflectix inside the cabinets, against the outer walls...and on the windows, skylights, and any other outer walls. We got SO cold, we had to turn it down at night!!
Of course, we kept the A/C unit down in the hold; just in case. You know Murphy's Law. If we take it home, we'd need it.