As Steve noted, don’t use tint film on the inside of double pane windows. We had a company do that not long after building our house and that company and the window mfr. had to negotiate replacing our big south-facing picture window. They used tinted glass (not film) for the new one instead.
We’ve found an external windshield cover makes a big difference while parked, especially if the coach isn’t facing north. Mounted outside, it won’t trap reflected heat against the windshield. But I know what you’re referencing. The cap over the windshield and audio/video products encapsulated therein get ridiculously hot; it caused our TV to often turned on by itself. I started keeping the right cabinet door open and entertained using a small fan to force ventilate the space, but it only helps heat up the living area.
As an addendum, if you have a plastic-cased Belkin power strip stuffed back in the cap behind your A/V devices, it’s advisable to replace it with a metal-cased one. A member here found out the hard way that if the plastic strip overheats or short circuits, it can more easily catch fire than a metal one, whose case can contain flames.
As to spray foam, I’d be reluctant for reasons that you expressed. Reflective wrap at least wouldn’t interfere much with any future changes or work. Fan ventilation might be more amenable/effective, especially if one could finagle an acceptable exhaust to the outside.
Joel
