I don't have an issue with using the ladder, as mine is light and stores in my bay almost as easily and out of the way as the small bag with the window and wiper covers; it takes about 10 minutes to remove and store the covers, and less to put them up, especially after doing it a couple of times. You don't exactly have to stand on the ladder's top rung and balance precariously to do this. Using a few turn-button attachment points rather than snaps makes it relatively easy, and as I've indicated before, our material has neither stretched nor shrank, so it goes on and off the buttons with minimal effort and yet fits snug and neat.
As to dirt, I've rinsed mine off a couple of times since I've had it, and only once did I lay it out and soft scrub it at all, after leaving it on during winter. Dust that settles and muddies a bit from a rainy spell just doesn't stick hard to this stuff. As to the interior and glass deterioration, that was when we used an interior cover on our old motor home, and admittedly it did not fit as tight as Henry and Leah describe it should. But it was Portland Oregon summer solar heat that built up between it and the glass, not Arizona. The ShadeMaster stops solar heat before it gets inside at all.
So you can see from this thread that there are many different opinions, most of them quite experienced. Inside or out will depend on your attitude toward ladders, storage, cleaning (or not), price, and which version keeps the most heat out - the main reason for getting a cover.
-Joel