I have experienced everything from overheated engines on the way up and overheated brakes on the way down, to snow flurries, nausea because of the many serpentines and total fatigue when driving in the dark with thick fog. A madness, what one sometimes took on. At that time, the trip was only worth it if you planned it as a 2-week tour with two to three customers per day. Nowadays, you fly to Pisa for 50 euros, take a rental car, visit the customers in the area and fly back the same evening.