Great idea. I have (in the past) taken a bucket with my micro fiber sponges and soap with me. I use the “spot free” rinse to fill the bucket part way and agitate the soap. Use remaining time to get the car wet with normal spray. Have to work with some expediency before the soap dries. Rinse off with a second spray, then flip the selector switch to Spot Free. Drive on the highway approx 5-10 minutes to air dry. Works good enough to please me.
When the weather improves, I sometimes use my power washer and foam cannon. Does a spectacular job. But such a hassle to get the hose, hookups, etc. But since I’m retired, I need something to do and always pleased with the results. In that regard, it’s worth it.