Might be worth a look at the itinary of the Scenic and Continental Milli Miglia tour which has two stops on the way down and two stops on the way back.
They don't specify which hotels they use, but the locations of the stops may help in your planning.
We did the drive last year but our trip was more leisurely as we took three stops each way. We stayed in Desenzano at the Hotel Benaco which was very good if a little distance out of the historic old town.
