Headed to Florence, Rome and Venice starting next week, and have only booked tour of Vatican. I understand that it is easy to pick up a guide near the Colosseum. We haven't booked tours because unsure we want to be walking around on a tour in what might be cold, rainy weather. Any advice appreciated because we probably would enjoy guides of Florence center, Ancient Rome and St Marks area. We have downloaded Rick's audios. Fire away--all opinions appreciated!!