I took the Colonia Express ferry from Buenos Aires for the day, I had heard mixed reviews from people on whether I should go rather than spend an extra day in Buenos Aires but I loved it. Why?
1) the historic core of Colonia del Sacramento is incredibly atmospheric on a sunny day, cobblestones and colours, beautiful tree and gardens. Its October on a Thursday and would definitely say come during the week when its more peaceful. It’s a tourist town but they do it well.
2) Old cars not in Cuba are here in Colonia. They add to the appeal in a subtle way. At the restaurant El Drugstore (which also has great colours) they even have tables inside for a tasty meal.
3) Uruguay left me wanting more… Maybe Colonia was an idealic taste but I’d love to find out and see more. If you can spend a few days and explore Montevideo and some of the coast.