The phrase "let's see how far we go" means to find out or discover the extent or limit to which something can progress or succeed. It expresses curiosity or uncertainty about how much progress will be made or how successful an endeavor will be. This can relate to physical distance, progress toward a goal, or metaphorical extent in various contexts. This expression is often used when embarking on a task or challenge and indicates openness to exploring possibilities and outcomes without predefined limits.

Additionally, the phrase is somewhat reminiscent of the theme in the Matchbox Twenty song "How Far We've Come," which reflects on progress over time and seeing the extent of achievement or change.