When to use "a" or "en" for places

[dupond]

Hi there

Could someone please help me with the following sentence?

"Ir de vinos" quiere decir ir con algunos amigos a tomar algo a un bar o a un cafetería."

Would the meaning be the same if it read "en un bar" and "en un cafetería?"

If not, what's the difference? Does the use of "a" as the preposition have anything to do with "ir" being in the sentence?


Thanks