The other day my boyfriend (he's from Zagreb) sent me a few songs in Rijeka dialect and other Istrian dialects and it turned out that I understand almost everything and had to translate the songs for him, even though I don't speak Croatian otherwise. I'm from Slovenian Istria, and it looks like Čakavian is much closer to my native dialect than Standard Slovene/Kajkavian/Standard Croatian. It's quite funny, but it looks like I would have almost no problems understanding people in Croatian Istria (unlike Zagreb, for example).
Here's a couple of the songs (I understand almost everything): https://www.youtube.com/watch?v=bXxJ9FGpUEghttps://www.youtube.com/watch?v=s1cyv8rqZFc
(Btw, I love this kind of music)
And I know this is probably a bit inappropriate since it's a Croatian thread, but here's a similar song in my native Slovene dialect: https://www.youtube.com/watch?v=lhzp7sZJyto