If you want to be as safe as possible:
- Take the option Bus instead of Metro, it allows you to wait outside and you can always decide to leave it or not board it if it’s too crowded.
- Alternately, rent or use a bike to reach the beginning of the walk, and change its itinerary at one point to make it a loop tour.
- Skip the visits inside or make a reservation if it’s open.
- Keep your distances and wear a mask.
- Be prepared to forget restrooms and restaurants. If not, having hand sanitizer will be useful.
- Walk early in the morning, late in the evening and/or during an off-rush hour weekday to have more space for you.
The time indicated for the walks will be reduced: they become trails that still allow you to discover the city but you will have to do them again later to be able to visit in detail as described.