GoPro Mic Question

So I'm looking at getting the GoPro Hero 4 and a mic to do some filming for shows I am going to this year. Kind of like a documentation to post to youtube. I have been researching all night and morning about external mics and the more I read the more confused I get to which I would like. I would like to have a wireless lavalier mic that I don't have to plug directly into the camera so that I can walk around freely if someone else is filming but we don't do a ton of walking so this is not a must. I just want to make sure our voices can be heard loud and clear when we go to put the videos together. Has anyone used an external mic or many and have a recommendation? Recommendation on a camera/recorder other than the gopro for this type of filming?