In this weather, I spray the lower part of the car (wheels, wheel arches, valances and sills) with TFR in a pressure washer, pressure rinse, then snow foam the whole car (inc. under arch) rinse again and towel dry. If the wheels are very dirty I may use a well diluted non acid wheel cleaner first. I try and keep the TFR from most of the body as it leaves drying marks and strips the wax too much. Not exactly detailing, but quick and do-able without getting on hands and knees (an advantage at my age).