Upon arriving at Colonia del Sacramento, I had realized that the guidebooks didn't offer much in terms of navigating around the town. I felt rather nervous when I exited the terminal - unsure of how to set foot towards the Historic Quarter.
With some guessing and obtaining a map from the currency exchange place next door (which was not scaled properly), there was no need for me to worry. You can walk up one of the streets, passing by 18 de Julio, and making a left at Avenida de General Flores. (You have the option of making a left at 18 de Julio - but the street is very residential, and you may feel wary of where you're heading).
On Avda. Gral Flores, I was rather surprised that Colonia del Sacramento had a downtown. Guidebooks only speak of its Historic Quarter. Lining Avda Gral Flores are several small businesses that serve both residents and tourists with hostels and currency exchange centers - note that many established businesses will accept the Argentine peso. But, be cognizant of the Argentine to Uruguayan peso rate
Within 5 - 10 minutes of walking along Avda. Gral Flores, you will start noticing several rentals for golf carts and bicycles - a wonderful option for a pleasant day. Ahead, you will see el Rio Plata and the Historic Quarter. If you had opted to walk along 18 de Julio, you will arrive at Puerta de Campo, the gates of Colonia del Sacramento.
The Historic Quarter is a small expanse of cobbled streets, preserved buildings and Although small in size, it's big on charm. It is difficult to get lost - you will not miss the major sites. In both the downtown area and the Historic Quarter are restaurants, cafes and souvenir shops. However, there's a stronger draw to shopping in the Historic Quarter.
Of special note, you will know that you are not far from Buenos Aires: stray dogs are abound in the Historic Quarter, just as in Buenos Aires.