wow, lots in a fuss about nothing. It's simple, if you want it to look nice it will cost you hundreds of dollars and more time to install each time and you'll have to go outside to do most of them. They'll wear with the weather.
As mentioned most outside don't reflect anything, they are just a sun blocker with many letting light in. They reduce the heat coming through the window but also get warm or even hot as they absorb the heat. Remember from simple grade school, dark colors absorb the heat, lighter colors reflect and don't absorb heat like dark colors. So there is still heat transfer to the windshield from the outside in.
The foil bubble insulation will simply reflect the heat right back out the windshield without absorbing it. So in my opinion and experience the foil on the inside stops the heat from the sun from coming in. When I install the bubble foil insulation in my window the heat blockage and cooling affect is immediate.
It doesn't look the greatest, but it works and its a cheap way to do what the OP wishes to achieve. I use these on my cars and trucks in the window for years without any windshield warping or degradation of any noticeable kind. Heck, you have more of a chance losing you windshield to a rock going down the road.
So when did owning a motor home mean you can't be frugal? Do what makes you happy.
