Where I live the water is hard with a high calcium content that leave white spots on the cars and trucks. For rinsing I have an Reverse Osmosis unit that charges up two 5 gallon pressure tanks for a spot free rinse. After rinsing with the power washer I chase this off with about 3 gallons of the RO water, works great.
I use a electric leaf blower to dry the vehicle. It does a really good job at removing the water from areas like door handles and mirrors. After I blow it off I may have to do some minor drying in a area like under a spoiler with a waffle weave microfiber cloth. The less you touch the paint the lower your chances are for swirls.