Good advice. The complex has a car washing station (that has some nice shade, no less) so I can wash the car anytime. Plus winter in Tucson or Phoenix means its about 60 degrees. So car washing is a year-round thing here.
I have some quick detailer (Mother's I think) that seems to work really well. I really only use it to get bugs off in between washings. However I do need some better microfiber towels. Mine are plenty soft, but they just have a lot of lint and fuzz.
BUT I have to disagree with you on a few points. First, the car cover is a must for any car kept outside in the Arizona sun. Especially a ragtop. There's lots of convertibles running around here that are great in the spring and fall, but once summer hits those tops go up, the AC goes on and they don't come down again until October. So from May to August at least, you have your top up and getting hammered by the sun. Only takes a few good summers of sun beating down to turn your black top grey. Also, the heat and intense UV will fry UV protectants both in waxes and fabric protectants like Raggtop MUCH quicker than in milder climates. Everyone has a different opinion, but having lived here for almost 20 years this is what I have observed.
I know the dangers of A) covering a dirty car and B) using a car cover when it's windy. So I always make sure my car is clean and waxed when I cover it. And I use a California Car Duster every time I put on the cover. I've used those dusters for years on our old 68 Chevelle that has almost the exact same dark blue paint as my Boxster (it was repainted a few years ago with a metallic paint and clear coated) and have never had them cause a single scratch or swirl if used properly. And the covered parking does help, but it really only keeps the sun and rain off. The sides are open and allows all sorts of dust and dirt to blow all over.
The trick with a car cover in my experience is to get one with a soft, slick inner layer that won't scratch and won't trap grit. I don't like covers that have the fuzzy inner layer because they just grab any bit of passing dust and rub in onto your paint. I prefer the Covercraft Weathershield covers as the inner layer is extremely slick and smoth, but it's not fuzzy. They do warn you to only cover the car clean and waxed, however. I also make sure I wash the cover often.