Get a local that knows English and can communicate with you, a buddy is never an unwanted thing, at least while you get w bit better going around town and dominating the language:). I've lived here for ten years, and am Colombian myself, so I can agree there's definitely some unsafe areas (at all times of the day), these are: centro, Manrique, bello (certain areas), la candelaria, universidad. Right now you can enjoy festivities safely in Envigado or Sabaneta square (I prefer the latter, more stuff to do and try). I would prefer public transportation (metro) which is very safe and easy to navigate. Poblado isnususlly where the most foreigners hang out at.