Han says “If we could find it on our scanners, the First Order’s not far behind”. And while that is a serviceable explanation, it is one throwaway line that happens nearly 17 minutes after Han first shows up. So a main character shows up in the movie and starts doing things, and it is only after a big chunk of time that we even get an explanation as to why & how he found the Falcon in the first place. That’s my complaint; I know that it eventually gets an explanation and makes sense, but this takes way too long. And it’s still convenient that he just happened to pick it up on his scanners.