1. accompany someone, agree with someone/to something, participate in an action (without full engagement)
came along for the ride, would you like to tag along?
In the U.S.A., a 'ride' is a journey (like a 'lift' in the U.K. or Ireland), so this expression refers to a kind of journey where you might accompany someone in what they are doing. It can be physically going somewhere, or following a course of action or an idea. We can use this expression in a number of contexts, but it's probably more suited to social situations.