Some travelers may scoff at a hop on hop off bus but I say don't write it off. If you need to see a lot of the city and quickly, this is the best way to cover a lot of ground with minimal effort. No calling Ubers or dealing with public transport.

You'll cross the whole city from La Boca to Nunez.

Obviously, as the name suggests, hop off wherever you want. My suggestion, if you book this bus, is to definitely hop off in La Boca to explore Caminito. You'd need a taxi to get there otherwise so this takes care of your transport for that site.

You can also hop off at the other end of the spectrum and tour River Plate's stadium in Nunez, see Barrio Chino in Belgrano, or just ride the full route to discover which places interest you to revisit later in your trip!