The normal sentence is "walking on/along the street". "Cruising up the avenue" has a colloquial, mildly poetical feeling about it. It might come from a song, for example. "Cruising" means travelling along, not being in a hurry. Cruising up the avenue might be walking, or it might be travelling in a car. "Up" and "down" can be used with streets/avenues to mean "along". Cruising down the avenue. Walking up the street. Both mean travelling along. "Up" and "down" might indicate that there is a hill, but not necessarily: they could be flat.